Charge generators in heterolamellar multilayer thin films

ABSTRACT

Multi-layered compositions having a plurality of pillared metal complexes disposed on a supporting substrate, the pillars comprising divalent electron acceptor moieties with a phosphonate or arsenate at each end. The pillars can be electron donating, electron accepting or charge generating in nature. Each layer of parallel pillars is separated by a layer of a group (IVA), (IVB), (IIIA) or (IIIB) metal or a lanthanide. The compositions can further comprise particles of at least one Group VIII metal at zero valence entrapped within each layer of the complex. The complexes can also incorporate &#34;stalactites&#34; and &#34;stalagmites&#34; of capped arsonato or phosphonato ligands interspersed with the pillars providing a series of interstices about each electron accepting group. The supporting substrate can be comprised of an organic polymer template. The complexes are useful for the conversion and storage of solar energy, for the production of photocurrents, and as catalysts for reduction reactions, for example, the production of hydrogen peroxide from oxygen and hydrogen gases, the production of H 2  gas from water, and the reduction of ketones to form alcohols.

This application claims priority to Provisional Application No.60/052,256 filed Jul. 11, 1997.

TECHNICAL FIELD

The present invention pertains to enhanced photovoltaic compositions,more particularly to multilayered, heterolamillar thin films and methodsof using same.

BACKGROUND OF THE INVENTION

Solar energy can be used and stored by the efficient production oflong-lived photo-induced charge separation--a state achieved inphotosynthetic systems by the formation of a long-lived radical pair. Anumber of artificial systems have been reported that efficiently undergophotochemical charge transfer, unfortunately, the thermal back electrontransfer often proceeds at an appreciable rate, limiting the utility ofthese systems. What is needed is a system which has very efficientphotoinduced charge transfer, and forms a charge-separated state whichis long lived in air. The charge separation in these systems typicallyinvolves a redox reaction between a photo excited donor and a suitableacceptor, resulting in the production of radical ion pairs illustratedby the formula:

    D+hv→D*                                             (1a)

    D*+A→A.sup.- +D.sup.+                               (1b)

    D.sup.+ +A.sup.- →D+A                               (2)

The cation and anion generated in this way are better oxidants andreductants, respectively, than either of the neutral ground-statemolecules. To harvest the light put into this system, the oxidizing andreducing power of the photo-generated species must be used before theelectrons are transferred back (equation 2) generating the startingmaterials. It is desirable to control this photochemically unproductivethermal fast back electron transfer reaction. One method has been toincorporate the donors and acceptors into solid matrices.

Design and characterization of chemically sensitive interfaces and thinfilms has focused on attempts to mimic the highly efficient processesobserved in biological systems, many of which occur in or at membranes.Thus, a key goal in this area is the fabrication of an artificial systemfor the conversion of solar energy into chemical or electrical energy.This approach to energy conversion can take a number of forms, rangingfrom the design of novel photovoltaic devices to the search for anefficient and cost-effective method to photochemically convert liquidwater to gaseous hydrogen and oxygen. Properly designed systems can usethe photoinduced charge separation to generate a photocurrent.

In a process to generate chemical energy, D⁺ and A⁻ are used to driveuphill chemical reactions, such as the oxidation and reduction of water,respectively. In order to generate electrical energy the same speciescan be used as the anode and cathode of a photocell. In order for eitherof these processes to be efficient back electron transfer (equation 2)must be prevented. In order to retard back electron transfer it isimportant to control both the structural and electronic properties ofthe system. In natural reaction centers this goal is achieved by fixedgeometrical arrangements of electron donors, intermediate carriers andelectron acceptors within the membrane. In artificial systems , theelectron donors and acceptors with chosen redox potentials may bearranged in a fixed geometry using simple self-assembly techniques.

The individual components in the charge separated state have theappropriate potentials to carry out the reduction and oxidation ofwater. Unfortunately, these direct reactions are kinetically limited,such that catalysts are required to overcome the kinetic barriers.Colloidal platinum particles are ideal catalysts for the reduction ofwater to give H₂. In systems used for photoreduction of water, the closecontact of high potential radicals formed in the compounds and Ptparticles is advantageous, because electron transfer from reducedviologen to Pt particles should compete effectively with back electrontransfer. These platinum particles may be present in the reactionsolution, incorporated into the structure of the compositions, or both.

Compounds which can carry out reduction reactions, using hydrogen gas astheir reducing equivalents, are useful as catalysts for the conversionof mixtures of hydrogen and oxygen to hydrogen peroxide. Hydrogenperoxide is a very large volume chemical. The United States annualproduction is greater than 500 million lbs. Several processes have beenpatented for the production of hydrogen peroxide, which depend on thetwo following reactions. The goal is to promote reaction (3) and retardreaction (4):

    H.sub.2 +O.sub.2 →H.sub.2 O.sub.2                   (3)

    H.sub.2 O.sub.2 +H.sub.2 →2H.sub.2 O                (4)

A number of catalysts for this conversion have been reported includingboth homogeneous and heterogeneous catalysts.

Compositions of the present invention are capable of producing asustained photoinduced charge separation state which renders thecompositions useful in solar energy conversion and storage. Multilayerthin films of the present invention composed of donor and acceptorlayers produce photocurrents when irradiated with light. In addition,the compositions permit reduction of various metal ions to produce thezero-valence metal in colloidal form entrapped in the matrices of thecompositions. These latter matrices containing the zero-valence metalhave a variety of uses such as in the decomposition of water to yieldhydrogen gas and the sensing of oxygen. In addition, the zero-valencemetal matrices can be used in catalysis, as for example in theproduction of hydrogen peroxide and the oligomerization of methane toform higher hydrocarbons.

SUMMARY OF THE INVENTION

The present invention provides multi-layered compositions, each layerhaving a plurality of parallel "pillars" comprising divalent electronacceptor or donor moieties with a phosphonate or arsonate at each end.Each layer of parallel pillars is separated by a layer of a group (IVA),(IVB), (IIIA) or (IIIB) metal or a lanthanide.

The complex can further comprise particles of at least one Group VIIImetal at zero valence entrapped within each layer of the complex. Thecomplexes can also incorporate "stalactites" and "stalagmites" of cappedarsonato or phosphonato ligands interspersed with the pillars providinga series of interstices about each electron accepting group.

The donor or acceptor moiety of each pillar layer can be selectedindependently from the other layers. Thereby films can be homogenous,where the donor/acceptor moiety of each layer is the same; orheterogenous, where the donor/acceptor moiety of one or more adjacentlayers can be different. The efficiency of the charge transfer isimproved with the addition of a charge generator layer located betweenadjacent donor layers and acceptor layers.

The complexes are useful for the the production of photocurrents,conversion and storage of solar energy, and as catalysts for reductionreactions, for example, the production of hydrogen peroxide from oxygenand hydrogen gases, the production of H₂ gas from water, and thereduction of ketones to form alcohols.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the highly ordered structure of asubstrate and film according to the present invention.

FIG. 2 is a schematic view of a solid composition incorporating"stalactite" and "stalagmite" ligands according to the presentinvention.

FIG. 3. is a schematic view of a solid of the present inventionincorporating metal particles and "stalactite" and "stalagmite" ligandsaccording to the present invention.

FIG. 4. is a schematic for the production of multilayered films.

FIG. 5. is a graph of the photochemical measurements of films of Example45.

FIG. 6. is a graph of the photochemical measurements of films of Example46.

FIG. 7. is a graph of the photochemical measurements of films of Example48.

FIG. 8. is a graph of the photochemical measurements of films of Example50.

FIG. 9. is a graph of the photochemical measurements of films of Example52.

FIG. 10. is a graph of the photochemical measurements of films ofExample 54.

FIG. 11. is a graph of the photochemical measurements of films ofExample 56.

FIG. 12. is a graph of the photochemical measurements of films ofExample 58.

FIG. 13. is a schematic view of a multilayer, thin film with a chargegenerator layer.

FIG. 14. is a schematic of possible charge transfer systems.

FIG. 15. is a schematic for producing a substrate with a linking means.

FIG. 16. is a schematic of an alternate chemistry method.

FIG. 17. is a schematic of preparing a charge generator layer.

DETAILED DESCRIPTION

In general the invention relates to layered compositions comprising twoor more adjacent metal layers, independently of the other, comprised ofatoms of a divalent, trivalent, or tetravalent metal of Group III, IVA,IVB having an atomic number of at least 21 or atoms of a lanthanide,which form a cohesive layer. The metal layers are adjacently spaced andin substantially parallel relation to each other and to the substrate.Disposed between, and in substantially perpendicular relation to themetal layers, are organic pillars which are independently, one from theother, covalently joined to two of the adjacent metal layers and thusforming interstices between the pillars and the two adjacent metallayers. This layered composition can take the form of, for example, athin film or a micro-crystalline solid.

The organic pillars are illustrated by the formula:

    --(Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3)--                 I.

each of Y¹ and Y², independently of the other, is phosphorous orarsenic;

Z is an electron accepting or donating divalent group containing aconjugated network which is capable of alternating between a stablereduced form and a stable oxidized form;

A sufficient number of anions are bound to the metal ions which make upthe metal layers, such that the metal ions have an effective valence offrom ⁺ 1 to ⁺ 6, preferably ⁺ 3 or ⁺ 4.

A separate group of anions is present within the lattice formed by thepillars and metal atoms to counterbalance any residual charge in thecomposition.

Additionally, the composition can comprise particles of at least oneGroup VIII metal at zero valance trapped in the interstices between thepillars and the adjacent metal layers. These particles may enhance thefunction of the composition, for example, by acting as a catalyst forreduction reactions. The compositions can also comprise organic ligandsdisposed between the metal layers and between the pillars which areindependently, one from the other, covalently joined to one of the metallayers. The ligands are illustrated by the formula:

    --Y.sup.3 O.sub.3 --R.sup.3                                II.

Y³ is phosphorous or arsenic and R³ is a non-reducible capping group.

In a first embodiment, the invention relates to a composite compositionin which a film is disposed on a supporting substrate. In that form, thelayer closest to the substrate is bound to the substrate by a linkingmeans. The substrate can be, for example metals, glass, silicas,polymers, semiconductors (e.g., silicon, gallium arsenide), combinationsthereof such as a gold layer on an aluminum base, and the like. Thesubstrate can be in any form, for example sheets, foils, plates, films,electrodes, colloidal particles in suspension, polymer templates, highsurface area supports, and the like. The surface of the substrate can beuniform (smooth) or non-uniform (rough). The film is composed of aplurality of pillared metal complexes, each of the formula:

    --L--[(Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3)Me.sup.Y ].sub.k ·k*p(X.sup.q-)                                   III.

in which:

L is a linking means;

each of Y¹ and Y², independently of the other, is phosphorus or arsenic;

Z is a divalent group which reversibly forms a stable reduced form andstable oxidized form;

X is anion;

Me^(Y) is Me¹ _(n) W_(m), where

Me¹ is a divalent, trivalent, or tetravalent metal of Group III, IVA, orIVB having an atomic number of at least 21 or a lanthanide;

W is an anion, such as, but not limited to, halides or pseudohalides, or--OH;

n is 1, 2, or 3;

m is 0, 1, 2, 3, or 4;

k has a value of from 1 to about 250;

p has a value of 0, 1, 2, or 3; and

q is the charge on the anion,

where for each additional k value, another layer is added to the film.

Me¹ can be, for example, a group IVA metal having an atomic number of atleast 21 such as germanium, tin, or lead, a group IVB metal such astitanium, zirconium, or hafnium, a group IIIA metal having an atomicnumber of at least 21 such as gallium, indium, or thallium, a group IIIBmetal such as scandium, yttrium, or a lanthanide as for examplelanthanum, cerium, praseodymium, etc. Of these, titanium, zirconium,hafnium, germanium, tin, and lead are preferred with zirconium beingparticularly useful.

Each of Y¹ and y² is phosphorus or arsenic, preferably phosphorus, eachof Y¹ O₃ and Y² O₃ thus being a phosphonato or arsonato group.

The group Z is divalent, being bound to the phosphorus or arsenic atomof the phosphonato or arsonato group defined by Y¹ O₃ and Y² O₃. Inpractice, the precise structure of the group Z is of lesser importancethan its electronic properties; Z must be capable of existing both in astable reduced form and reversibly in a stable oxidized form.

In one embodiment, Z can contain two conjugated cationic centers whichtogether have a negative E°_(red) value; i.e., a reduction potentialbelow that of hydrogen. The two conjugated cationic centers can be forexample tetravalent nitrogen atoms which are conjugated ring members inan aromatic ring system. In one embodiment, each tetravalent nitrogenatom is a ring member in a separate aromatic ring system and two suchring systems, which can be of the same or different structure, arejoined to one another directly through a covalent bond. Each sucharomatic ring system can be a monocycle such as pyridine, pyrazine, orpyrimidine. Alternatively, each aromatic ring system can be a fusedpolycycle in which a pyridine, pyrazine, or pyrimidine ring is fused toone or more benzo or naphtho ring system, as for example quinolinium,isoquninolinium, phenanthridine, acridine, benz[h]isoquinoline, and thelike.

The two aromatic ring systems, which can be of the same or differentstructure, alternatively can be linked through a divalent conjugatedsystem as for example diazo (--N═N--), imino (--CH═N--), vinylene,buta-1,3-diene-1,4-diyl, phenylene, biphenylene, and the like.

In a further embodiment, the two conjugated cationic centers can be in asingle aromatic system such as phenanthroline, 1,10-diazaanthrene, andphenazine.

Typical dicationic structures suitable as Z thus include2,2-bipyridinium, 3,3-bipyridinium, 4,4-bipyridinium, 2,2-bipyrazinium,4,4-biquinolinium, 4,4-biisoquninolinium,4-[2-(4-pyridinium)vinyl]pyridinium, 4,4'-bis(4-pyridinium) biphenyl,and 4-[4-(4-pyridinium)phenyl]pyridinium.

The aromatic systems in which the two conjugated cationic centers arelocated can be unsubstituted or substituted, as for example with alkylof 1 to 6 carbon atoms or alkoxy of 1 to 6 carbon atoms. Suchsubstitution can be inert or can have an effect on the reductionpotentials of the cationic centers sterically or through induction.

While the two cationic centers must be linked through conjugation, theentire system comprised by Z need not be conjugated. Thus Z can bejoined to each of Y¹ O₃ and Y² O₃ through a conjugated or non-conjugatedbridge. Hence one highly desirable structure for Z is characterized bythe structure:

    --(R.sup.1).sub.n --Z'--(R.sup.2).sub.m--                  IV.

in which Z' is a divalent aromatic group containing at least twoconjugated tetravalent nitrogen atoms; each of n and m, independently ofthe other, has a value of 0 or 1; and each of R¹ and R², independentlyof the other, is a divalent aliphatic or aromatic hydrocarbon group.Typically each of n and m will be 1 and each of R¹ and R², independentlyof the other, will be a straight or branched divalent alkane chain ofsix or less carbon atoms, as for example methylene, ethano,trimethylene, propane-1,2-diyl, 2-methylpropan-1,2-diyl,butane-1,2-diyl, butane-1,3-diyl, tetramethylene, and the like or adivalent aryl, substituted or unsubstituted, as for example benzyl.

Other forms of Z include 1,4-Bis(4-phosphonobutylamino)benzene (PAPD);porphyrin derivatives and phthalocyanin derivatives. Using ringed Zmoities would result in pillars illustrated by the formula: ##STR1##where X is O or (CH₂)_(y) where y is 1 to 6.

The group X is an anionic group one or more of which (depending on thevalue of k and the charge of X) will balance the cationic charges of Z.and result in a net positive valence of Me^(Y) being equal to (4-p*q).The precise nature of X is relatively unimportant and X can be forexample a halogen anion such as chloride, bromide, and iodide, apseudohalide, sulfate, sulfonate, nitrate, carbonate, carboxylate, etc.

The group W is an anionic group one or more of which (depending on themetal ion, Me¹, used) will result in a net positive valence of Me^(Y)being equal to (4-(p*q)). The precise nature of W is relativelyunimportant and W can be for example a halide, a pseudohalide, hydroxy,etc.

Each complex depicted by Formula III is bound to the substrate throughthe depicted linking means; the plurality of --L--Y¹ O₃ --Z--Y² O₃Me^(Y) units on the substrate, thereby produces a pillared structure.Each complex can contain one Z-containing unit ("pillar"), in which casek has a value of 1, but preferably k has a value in excess of 2 so thatthe unit --(Y¹ O₃ --Z--Y² O₃)Me^(Y) -- becomes the monomer of thepillared polymeric complex in which k ranges from 2 to about 250,typically from about 5 to about 100. This multilayered structure can beillustrated by the formula: ##STR2## Such films can be prepared throughsequential adsorption reactions analogously to those described by Ronget al., Coordination Chemistry Reviews, 97, 237 (1990). The syntheticmethod and stoichiometry used can effect and determine the resultingconfiguration and morphology of the compositions.

FIG. 16 illustrates one method for producing a substrate with a linkingmeans. An example preparation method begins with a substrate, whichtypically is hydroxy terminated, as for example metals (the surfaces ofwhich invariably include the metal oxide), glass, silicas, galliumarsenide, and the like, which is first derivatized with ahydroxy-reactive reagent which introduces the linking means L orcomponents of that linking means. Typically the distal portion of L willterminate in, and thus eventually be bound to Y¹ O₃ through, a metalatom Me³ which is similar to Me¹, i.e., a divalent, trivalent, ortetravalent metal of Group III, IVA, or IVB having an atomic number ofat least 21, or a lanthanide.

Thus for example, the substrate can be treated with a compound of theformula:

    X"--R.sup.1 --Z--Y.sup.3 O.sub.3 H.sub.2.2X'               VI.

in which R¹ and Z are as herein defined; Y³ is phosphorus or arsenic; X'is an anion analogous to X (X' can be, but need not necessarily be, thesame anion as will appear in the final complex) and X" is a reactivehalogen such as chloro or bromo. Thereby produced is the intermediate:

    substrate--O--R.sup.1 --Z--Y.sup.3 O.sub.3 H.sub.2.2X'     VII.

The foregoing reactions can be conducted in two stages, first bytreating the substrate with a compound of the formula X"--R¹ --Z.2X' andthen treating the product with a phosphoryl halide such as phosphorylchloride or phosphoryl bromide or a corresponding arsonyl halide.

In either aspect of this embodiment, the linking means produced issimilar to the repeating unit insofar as it contains --Z--Y³ O₃.

Alternatively, the linking means can be dissimilar to the repeatingunit. Thus the substrate can be treated with a silane such as anaminoalkyltrialkoxysilane as for example 3-aminopropyltriethoxysilaneand this derivatized substrate then treated with a phosphoryl halidesuch as phosphoryl chloride or phosphoryl bromide or a correspondingarsonyl halide to produce:

    [substrate]--alkyl--NH--Y.sup.3 O.sub.3 H.sub.2            VIII.

Other examples of linking means include:

    [substrate]--O--alkyl--Y.sup.3 O.sub.3 H.sub.2.            IX.

    [substrate]--alkyl--O--Y.sup.3 O.sub.3 H.sub.2             X.

The substrate can also be treated with a thiol to form the linkingmeans. Such thiol linking are particularly useful on gold substrates.Examples of such thiols include thiophosphonic acids having the formula:HS--(CH₂)n--PO₃ H₂ or thioalkylsilanes having the formula:HS--(CH₂)n--Si(O--alkyl)₃, where n is 1 to 16 and alkyl is a straight orbranched alkyl of 1 to 16 carbon atoms. Using such thioalkylsilanesresults in a linking means intermediate presenting hydroxy groups forthe attachment of the metal layer.

Another embodiment uses a template of an organic polymer as a linkingmeans for binding the compositions/films to the surfaces of hydrophobicsubstrates (e.g., quartz, silicon and metals). These polymer templatesare derivatized with phosphonate or arsonate groups, for example, bytreating epoxide groups pendant to the polymer backbone with phosphoricacid to yield pendant phosphates.

The hydrophobic polymer template is adsorbed at the surface of thehydrophobic substrate leaving the hydrophilic phosphonate/arsonategroups free for cross-linking. These pendant phosphonate or arsonategroups are cross-linked with ions of the divalent, trivalent, ortetravalent metal of Group III, IVA, IVB having an atomic number of atleast 21 or of a lanthanide which form a first metal layer. Thesepolymer templates show good adhesion to the substrate surface, and ayield a highly porous structure (especially on metal substrates).

The polymer can be any polymer having side chains which are capable ofbeing derivatized with phosphonate or arsonate groups. A preferredpolymer is polyvinylpyridine in which a fraction, preferably less thanone half, of the pyridyl groups have been alkylated with X(CH₂)_(n) PO₃H₂, where X is an anion and where n can be 1 to 16, preferably 2 to 4,(abbreviated PVP--C_(n) P). A polymer backbone which has pendent thiolgroups, is preferred for enhanced binding to Au, Ag, and Pt substrates.

In another embodiment, the substrate can be the polymer template itself.Films grown on the polymer template are grown in solution. Thehydrophobic properties of the polymer backbone cause the polymer insolution to aggregate into sheet form, with the pendant hydrophillicphosphonate or arsonate groups extending out into the solution,resembling lipid bilayers. This structure can be illustrated by theformula: ##STR3##

Colloidal particles of a Group VIII metal, preferably platinum, can bepresent in the solution. The hydrophobic properties of the aggregate ofthe polymer backbone attracts the particles. The particles are thentrapped within the hydrophobic environment between polymer backbones.This structure can be illustrated by the formula: ##STR4##

In either case, the substrate, having a surface rich in phosphonate orarsonate groups then is treated with a reagent providing Me³ ions, e.g.,zirconyl chloride. The metal ions bind to, and effectively cross-link,the phosphonate or arsonate groups, in turn producing an intermediatehaving a metal rich surface and characterized as "substrate--L'--Me³ "in which L'--Me³ corresponds to linking means, L, of Formula III,providing a means which (I) on the one hand binds to the substrate and(ii) on the other presents a metal Me³ for further complexing.

Formation of Layers

Individual layers of donor, acceptor and charge generator are applied tothe prepared substrate, following t he scheme illustrated in FIG. 4.

Continuing the process from above, the substrate-L is then separatedfrom the reagent providing Me³ ions, washed with water, and treated witha solution of a bisphosphonic acid or bisarsonic acid of the formula:

    H.sub.2 Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3 H.sub.2.2X'   XIII.

in which Y¹, Y², Z, and X' are as defined above. This reaction iscomplete within a few hours, as for example about 4 to 5 hours, and canbe accelerated through the use of moderate heat, as for example fromabout 80 to about 100° C. The deposition of this layer can be readilymonitored spectrophotometrically at wavelengths of from about 260 toabout 285 nm. For consistency, generally the range of 280-285 nm isemployed. One of the --Y¹ O₃ H₂ and --Y² O₃ H₂ groups binds to the metalrich surface, while the other remains uncoordinated, thereby nowproducing an intermediate having a surface rich in phosphonate orarsonate groups. This intermediate can be depicted as:

    substrate--L'--Me.sup.3 --Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3 H.sub.2.2X'XIV.

The substrate--L'--Me³ --Y¹ O₃ --Z--Y² O₃ H₂.2X' is removed from thesolution of the bisphosphonic acid or bisarsonic acid, rinsedthoroughly, and then treated with a reagent providing Me¹ ions toproduce a complex of Formula III in which k is 1.

The foregoing sequence of the last two synthetic steps, that istreatment with a bisphosphonic acid or bisarsonic acid followed bytreatment with a reagent providing Me¹ ions, is repeated to producecomplexes having higher k values. Absorbance, as for example at 280-285nm, appears to increase linearly with the number of layers and providesa convenient method of monitoring the formation of multilaminarcompositions.

The foregoing procedure is readily and preferably modified to entrapatoms of at least one Group VIII metal, as for example platinum,palladium, iron, cobalt, nickel, ruthenium, rhodium, osmium, or iridium,at zero valence within the complexes. Thus following treatment with abisphosphonic acid or bisarsonic acid but before treatment with areagent providing Me¹ ions, the sample is immersed in an aqueoussolution of a soluble anionic salt of the Group VIII metal. After ashort time, the metal anion exchanges with some of the chloride anionsin the sample. The stoichiometrics of this exchange will depend upon therespective valences of the two anions. The platinum tetrachloride andplatinum hexachloride anions, for example, each have a valence of -2 andif chloride were the starting anion, one anion of either of these metalanions would exchange for two chloride anions.

Following this exchange, treatment with a reagent providing Me¹ ionsthen is performed as described above. As above, these reactions arerepeated until the desired k value is attained. The composite is thensimply exposed to hydrogen gas which reduces the metal anion to producethe metal in a zero valence state and colloidal form within the matrixof the composite. As noted previously, such materials are highlyeffective as catalysts in the production of hydrogen peroxide, theoligomerization of methane to form higher hydrocarbons, thedecomposition of water to yield hydrogen gas, and the sensing of oxygen.The compositions also can be utilized to reduce various organicsubstrates.

When growing the layered compounds on a polymer template as thesubstrate, the above processes are generally followed, however, thesequential treatment steps are separated by dialysis steps to removeunused reactants, not by rinsing.

It is possible to utilize more than one Group VIII metal in any sample,either using soluble salts of different Group VIII metals in one or moreexchanges or conducting one or more exchanges with a first Group VIIImetal and subsequent exchanges with a different Group VIII metal. Thuscreated upon eventual reduction are unique compositions in whichcolloidal particles of two Group VIII metal having different chemicaland electronic properties are entrapped in a single matrix.

The process shown in FIG. 4 involves the growth of metalphosphonate/arsonate thin film layers; however, other chemistries can beused to fabricate the thin films layers. For example, thiols could beused in place of phosphonate/arsonate groups. The result would be ametal sulfide [M(S--R--S)_(n) ] thin film. The same sort of chemistrywould need to be used with the charge generator to insure good alignmentof the charge generators. An example of this alternate chemistry isillustrated in FIG. 17. This approach can be used to grow donor,acceptor, and charge generator thin film layers. The advantages of thesenovel growth chemistries (i.e., metal thiolates) is that they producematerials with significantly higher conductivities, leading to improveddevice performance.

One preferred embodiment of these layered compounds, where Z is aviologen, was found to be very efficient at collecting solar radiationand converting that into stored chemical energy. The active wavelengthsfor this process are in the ultraviolet portion of the spectrum. Theenergy storage reaction is evidenced by a deep blue color developing inthe solid, which persists for long periods of time in the air. This bluecolor is due to a reduced viologen compound. Reduced viologen reactsrapidly with oxygen when prepared in solution, but is not reactive inthe solid because it is trapped inside the dense solid. Oxygen and otherexternal agents are unable to gain access to the reactive interiorlayers of the solid.

Another preferred embodiment of these layered compounds have aheterolamellar structure. By varying the composition of the pillarlayers, primarily by varying Z for each layer, compositions capable ofproducing a photocurrent are produced. The basic structure is to haveone layer of an electron donor composition and a second layer of anelectron acceptor composition; the order, i.e., substrate-donor-acceptoror substrate-acceptor-donor, determines the direction of the currentflow. One variation on the basic structure is to have several layers ofdonor (or acceptor) and then several layers of acceptor (or donor),essentially producing thicker donor and acceptor layers. This variationimproves photovoltaic properties by increasing the amount of lightabsorbed. Another variation has repeating, alternating layers of one ormore donor layers and one or more acceptor layers (or the oppositeorder), for example substrate-donor-acceptor-donor-acceptor- etc. (orsubstrate-acceptor-donor-acceptor-donor- etc.). In these compositionsthe electron donor/acceptor property of each layer is relative and notabsolute. Thus, a composition could have layers which all are generallyconsidered to have acceptor properties when viewed independently;however, if the layers are formed in, for example, a gradient order ofacceptor strength, the first layer would act as a donor in relation tothe second layer; the second layer would behave as a donor in relationto the third layer, etc. Compositions using this gradient variationcould be illustrated, for example, by the formula:

substrate-donor-donor'-donor"-acceptor-acceptor'-acceptor"-etc. Thegradient layers wil hinder back electron transfer and enhance thecurrent flow through, and eventuallly out of, the film.

In a preferred embodiment, the efficiency of the charge transfer betweendonor(s) and acceptor(s) is improved by incorporating a charge generatorlayer between donor and acceptor layers. The incorporation of a chargegenerator increases the quantum yield for charge separation in the thinfilm materials. A preferred thin film is comprised of a region of one ormore donor layers connected to a region of one or more acceptor layerswith a charge generator layer. This thin film structure is illustratedin FIG. 14.

A charge generator layer is similar in structure to a donor/acceptorlayer comprised of pillar-substituted metal phosphonate/arsonate,wherein the "pillar" has the characteristic wherein it's excited statehas a large dipole moment, which creates a large local fieldfacilitating electron transfer. The charge generator can be excited bydirect absorption of light or it can have the excitation transferred toit from an excited donor or acceptor (FIG. 15). Examples of materialsuseful as charge generators in multilamellar thin films include, but arenot limited to, stilbazolium compounds, assymmetric diazo compounds andother materials. Some preferred compounds which are useful as chargegenerators are illustrated by the following formulas:

Stilbazole ##STR5## Asymmetric Diazo ##STR6## where R₁ and R₂ aresuitably reactive such as: --PO₃ H₂, --AsO₃ H₂, --SH, --NH₂, etc.

Example of a synthetic methods for preferred asymmetric diazo chargegenerator materials follow the process: ##STR7##

Example synthetic methods for preferred stilbazole charge generatormaterials follow the process: ##STR8##

These materials have two resonance forms; the uncharged form is expectedto be the dominant form in the ground state, while the zwitterionic oneshould be the form in the excited state. For example, the direction andmagnitude of dipole moments of phenoxide analogs of a preferredstilbazolium compound are illustrated below:

The dipole moment of the charged resonance form is preferrably large andin the opposite direction of that of uncharged resonance form. When acharge generator material is placed at the interface between the donorand acceptor region of a multilamellar structure, the high dipole fieldform (i.e., high electric field) will induce charge transfer from thedonor to the acceptor region, as illustrated in FIG. 15.

Preferred charge generator materials are prepared as asymmetriccompounds that will facilitate the growth of highly oriented thin films;layers of these charge generator "pillars" are formed in sequence withdonor layers and acceptor layers in multilamellar thin films. To grow afilm layer of the charge generators (e.g.,a stilbazolium compound) it ispreferrable that the "pillars" be deposited in a well aligned fashion.This can be accomplished by using charge generator compounds which havechemically distinct ends. For example, a phosphonate group on one end ofthe charge generator "pillar" is used to bind the one end of themolecule to the exposed metal surface of the last formed donor/acceptorfilm layer. An amine group used at the other end of the charge generator"pillar" is then turned into a phosphonate/arsonate by treatment withPOCl₃ or AsOcl₃ and lutidine. The surface can then be treated with ametal complex, such as ZrX₄ to give a metal rich surface. This processis illustrated in FIG. 18. Thereby the method for forming a chargegenerator layer is the same as illustrated in FIG. 4, except that anextra step is added to convert the amine group to aphosphonate/arsonate. This method can be used to preparedonor/charge-generator/acceptor films as shown in FIGS. 14. The excitedstate of the charge generator will inject holes and electrons into thedonor and acceptor films, respectively. While FIG. 14 shows only oneorientation of the charge generator, if the films are grown with theacceptor layer first, the charge generator can be grown with theopposite orientation by preparing the charge generator compound with thephosphonate/arsonate on the imine end and the free amine group on thedivinylamino end.

Solid Complexes

In order to make it possible to utilize the stored chemical energy inthese compounds, a second embodiment comprises a more open structure.The advantage of the open structures is that they will allow externalreagents to have ready access to the photo-generated chemical energy.These solids are composed of a mixture of the pillars of the firstembodiment further comprising other smaller ligands interspersed amongthe pillars. These smaller components leave open space in this newsolid. A wide range of different smaller components having differentproperties and sizes can be used to prepare these solids, leading to avery diverse family of solids. The general formula for the materials ofthis second embodiment is:

    [[(Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3).k*p(X.sup.q-)].sub.1-n (Y.sup.3 O.sub.3 R.sup.3).sub.2n Me.sup.Y ]                        XV.

wherein

each of Y¹, Y², Z, X, Me^(Y), p, and q, are as defined above:

Y³ is phosphorus or arsenic;

n has a value of from 0.1 to 0.8; and

R³ is a nonreducible capping group.

In contrast to the materials of the first embodiment which arepreferably produced as films on a substrate, the materials of the secondembodiment are preferably produced as crystalline or amorphous solids.Analogously to the films of the first embodiment, however, zero valenceGroup VIII metals can be incorporated in these matrices.

As is apparent from Formula XV, two distinct ligands complex the metalsMe¹ and Me². The first of these is analogous to that utilized in FormulaIII, namely Y¹ O₃ --Z--Y² O₃, and each such ligand is capable ofcomplexing with two metal atoms. The second ligand, Y³ O₃ R³, is capableof complexing with only one metal atom. Thus the overall structure maybe viewed as a series of parallel layers of the metals Me¹ and Me² withthe Y¹ O₃ --Z--Y² O₃ groups serving as pillars. Extending from the metallayers between these pillars are the Y³ O₃ R³ groups, forming as it werea series of "stalactites" and "stalagmites" between the pillars. Theresultant structure thus has a series of interstices about each --Z--group. The dimensions of these interstices and the hydrophobicity oftheir defining surfaces can be controlled through selection of R³. Thusone can select relatively small R³ groups such as methyl, creatinglarger interstices, or relatively larger R³ groups such as phenyl orbenzyl, thereby producing relatively smaller interstices. Similarly, onecan impart hydrophobic properties to the defining surfaces of theinterstices by employing a hydrocarbon group such as propyl for R³ oralternatively decrease the hydrophobicity by employing an R³ group whichis substituted with a hydrophilic group such as carboxy. Examples ofsuitable R³ groups include, but are not limited to: H, CH₃, CH₂ Cl, CH₂CH₃, CH₂ CH₂ CH₃, OH, O⁻, and OCH₃.

Because of these interstices, it is possible to introduce Group VIIImetals after formation of the complexes, rather than after each step,and then reduce these to zero valence as described above. Hence acomplex of Formula XV is treated with an aqueous solution of a solubleanionic salt of a Group VIII metal and the resulting composition treatedwith hydrogen to produce the Group VIII metal in colloidal form. Thesecompositions can be used as catalysts as previously described.

Moreover, these interstices permit the passage of various molecules intothe complexes. For example, oxygen can enter into the matrices and thenoxidize the --Z-- groups. Since the reduced form of the --Z-- group arecolored while the oxidized form is white or yellow, this phenomenon canbe used to detect oxygen at extremely low levels.

In addition, the ability to control the dimensions of the intersticespermits the use of these materials in effecting selective reactions. Forexample, it is possible to selectively reduce acetophenone in a mixtureof acetophenone and 3,5-di-tert. butylacetophenone if the dimensions ofthe interstices are selected to permit passage of the former moleculebut not the latter, more bulky, molecule.

The complexes are readily prepared by treating a mixture of R³ Y³ O₃ H₂and H₂ Y¹ O₃ ∇Z∇Y² O₃ H₂ in the desired molar ratio with a source ofmetal ions. The reaction can be conducted either by refluxing orhydrothermally and the products are readily isolated and purified.

These porous solids show no photochemical activity in the air due to theready diffusion of oxygen into the interior of the solid. If the poroussolids are irradiated with ultraviolet light under anaerobic conditionsthe same active species, i.e., reduced electron acceptor, observed forthe dense solid is formed. Interestingly, the photochemical efficiencyof these open solids is much greater than the dense materials. If theporous solids which were irradiated under anaerobic conditions aretreated with air, they are rapidly bleached. Oxygen can freely diffuseinto the solids and react with the photo-generated reduced electronacceptor. The product of the reaction between the reduced electronacceptor and oxygen is hydrogen peroxide. One could thus use thesematerials as catalysts for photochemical production of hydrogenperoxide.

It would be desirable to extract the photochemically stored energy bygenerating mobile high energy chemical species that could diffuse out ofthe solid. The goal is to incorporate colloidal metal particles into thepreferred viologen containing solids. These metals are well known to actas catalysts for the reaction of reduced viologen with water to producehydrogen gas. Experiments successfully showed that the materials of thesecond embodiment could be used to convert solar energy into chemicalenergy in the form of hydrogen gas. The process involved: 1)photo-generation of reduced viologen, 2) electron transfer from reducedviologen to the colloidal metal particle, 3) protonation of the metalparticle and 4) elimination of hydrogen gas. Being a true catalyst thesematerials will accelerate both forward and reverse reactions equally,thus if of "metallized" material is treated with hydrogen some amount ofreduced viologen is generated. On this basis these materials can be usedas reducing agents. Photochemical energy is not needed to producereduced viologen: hydrogen can be used to achieve the same result. Theprocess for this chemical generation of reduced viologen is thus: 1)addition of hydrogen to the metal particle, 2) electron transfer fromthe metal particle to the viologen molecule forming reduced viologen,and 3) deprotonation of the metal colloid. Experiments have shown thatthe viologen molecules of these materials can be quantitatively reducedwith hydrogen gas at atmospheric pressure.

Schematic drawings of these porous solids are shown in FIGS. 2 and 3.

The following examples will serve to further typify the nature of theinvention but should not be construed as a limitation on the scopethereof which is defined solely by the appended claims.

EXAMPLE 1

Diethyl 2-bromoethylphosphonate (25 g) and 4,4' bipyridine (7.35 g) in125 mLs of water are refluxed for three days. An equal volume ofconcentrated hydrochloric acid is added and reflux continued for severalhours. The solution is concentrated to 120 mLs by atmosphericdistillation and 550 mL of isopropanol are added dropwise with stirringwhile chilling the mixture in an ice bath. The solid which forms iscollected by vacuum filtration and washed with cold isopropanol to yield1,1'-bisphosphonoethyl-4,4'-bipyridinium dichloride. (¹ H NMR (D₂ O)9.1(d), 8.5(d), 4.2(m), 2.0(m) ppm; ¹³ C NMR(D₂ O) 151, 147, 128, 58, 30ppm; ³¹ P NMR(D₂ O) 17.8 (s) ppm; IR (KBr) 3112, 3014, 1640, 1555, 1506,1443, 1358, 1281, 1175, 1112, 1020, 936, 816, 485 cm⁻ 1.)

In a similar fashion, utilizing 2,2-bipyridinium, 3,3-bipyridinium,2,2-bipyrazinium, 4,4-biquinolinium, 4,4-biisoquninolinium,4-[2-(4-pyridinium)vinyl]pyridinium, and4-[4-(4-pyridinium)phenyl]pyridinium, there are respectively obtained1,1'-bisphosphonoethyl-2,2-bipyridinium dichloride,1,1'-bisphosphonoethyl-3,3-bipyridinium dichloride,1,1'-bisphosphonoethyl-2,2-bipyrazinium dichloride,1,1'-bisphosphonoethyl-4,4-biquinolinium dichloride,1,1'-bisphosphonoethyl-4,4-biisoquninolinium dichloride,1-phosphonoethyl-4-[2-(1-phosphonoethyl-4-pyridinium)vinyl]pyridiniumdichloride, and1-phosphonoethyl-4-[4-(1-phosphonoethyl-4-pyridinium)phenyl]pyridiniumdichloride.

Other cationic species, such as the corresponding dibromides ordisulfates are obtained by substituting the corresponding acids, such asconcentrated hydrobromic acid or sulfuric acid, for hydrochloric acid inthe procedure of this example.

EXAMPLE 2

Planar substrates of fused silica (9×25 mm) are cleaned in a 1:3solution of 30% hydrogen peroxide and conc sulfuric acid, dried at 200°C. for one hour, and then treated with a refluxing solution of 2% (v/v)3-aminopropyltriethoxysilane in 50 mL of octane for 20 minutes.

The substrates are rinsed with octane and acetonitrile and treated for12 hours at room temperature with a solution of 10 mM each of phosphorylchloride and 2,6-lutidine in acetonitrile. After rinsing in water, thesubstrates are treated with a 65 mM solution of zirconyl chloride forthree hours at room temperature.

The foregoing procedure can be used to prepare multilayer films on othersubstrates such as silicon wafers and vapor deposited gold films.

The substrate next is subjected sequentially to the following two steps.

A). After removal of the solution of zirconyl chloride, the samples arethoroughly rinsed with deionized water and treated with 6 mM of1,1'-bisphosphonoethyl-4,4'-bipyridinium dichloride at 80° C. for 4hours and then thoroughly rinsed with deionized water. (Absorption ismeasured at 284 nm after treatment, the measured extinction coefficientfor 4,4'-bipyridinium bisphosphonate being 24,000 M⁻¹ cm⁻¹ at 265 nm.)

B). The samples next are treated with a 65 mM zirconyl chloride solutionat room temperature for one hour and again thoroughly rinsed withdeionized water.

Upon completion of one cycle of steps A and B, a plurality of a metalcomplex of Formula III in which k is 1 is obtained on the planar silicasupporting substrate. Each repetition of steps A and B increases thevalue of k by one. The number of layers, and thus the number of cycles,correlates to absorbance at 284 nm, as can be seen from the following:

    ______________________________________                                        No. of Layers  Absorbance                                                     ______________________________________                                        0              0.057                                                          1              0.083                                                          2              0.091                                                          3              0.109                                                          4              0.130                                                          5              0.152                                                          6              0.177                                                          7              0.201                                                          8              0.217                                                          9              0.242                                                          10             0.263                                                          11             0.281                                                          12             0.299                                                          13             0.327                                                          14             0.341                                                          15             0.357                                                          16             0.367                                                          17             0.373                                                          18             0.383                                                          19             0.407                                                          20             0.423                                                          21             0.452                                                          22             0.458                                                          ______________________________________                                    

EXAMPLE 3

By substituting 1,1'-bisphosphonoethyl-4,4'-bipyridinium dibromide inthe procedure of Example 2, a series of multilaminar compositions areobtained having the following absorbances:

    ______________________________________                                        No. of Layers  Absorbance                                                     ______________________________________                                        1              0.083                                                          2              0.098                                                          3              0.113                                                          4              0.157                                                          5              0.182                                                          6              0.239                                                          7              0.286                                                          8              0.350                                                          9              0.353                                                          10             0.391                                                          11             0.465                                                          12             0.557                                                          ______________________________________                                    

EXAMPLE 4

High quality films also are obtained by employing other metals in placeof zirconium in step B, e.g., hafnium, titanium, tin, gallium, etc, asshown in the following procedure.

Planar fused silica substrates (9×25 mm) are cleaned as described inExample 2 and a layer of 3-aminopropyltriethoxysilane is depositedthereon from the gas phase using the method of Haller, J. Am. Chem.Soc., 100, 8050 (1978). The substrates are phosphorylated as describedin Example 2, rinsed, and treated with 10 mL of a 65 mM aqueous solutionof hafnyl chloride for three hours at room temperature.

Alternating treatments with (A) an aqueous solution containing 6 mM1,1'-bisphosphonoethyl-4,4'-bipyridinium dibromide and 20 mM sodiumchloride at 80° C. for 4 hours and (B) a 65 mM aqueous solution hafnylchloride at room temperature for 1 hour, with thorough rinsing withdeionized water after each, then produce a series of multi-laminarcompositions which can be characterized spectrophotometrically at 284nm.

    ______________________________________                                        No. of Layers  Absorbance                                                     ______________________________________                                        1              0.052                                                          2              0.086                                                          4              0.175                                                          6              0.250                                                          8              0.304                                                          10             0.384                                                          12             0.518                                                          ______________________________________                                    

EXAMPLE 5

The procedure of Example 2 is modified after one or more executions ofstep A but before execution of the corresponding step B by immersing thesamples in a 6 mM aqueous solution of dipotassium platinum tetrachloridefor 0.5 hour thereby exchanging one platinum tetrachloride anion for twochloride anions. Step B then is performed as described in Example 2.

After completing the final cycle of steps A and B, the composite issuspended in water and hydrogen gas is bubbled through the mixture fortwo hours. The platinum is reduced to a zero valence colloidal stateentrapped in the overall matrix.

EXAMPLE 6

Silica particles (1 g) are heated in a drying oven for one hour and thenstirred with 150 mL of an aqueous solution (60 mM) of zirconyl chloridewith the silica (1 g) at 60° C. for two days. The solid is isolated byfiltration or centrifugation, washed three times with 150 mL ofdeionized water, and treated with 150 mL of a 20 mM solution of the1,1'-bisphosphonoethyl-4,4'-bipyridinium for six hours at 65° C. withagitation. The solid is separated from the aqueous solution and washedthree times with deionized water.

The solid then is treated with 150 mL of a 20 mM solution of potassiumplatinum hexachloride for three hours at room temperature, therebyexchanging one platinum hexachloride anion for two chloride anions.

One hundred and fifty milliliters of a 60 mM solution of zirconylchloride are added to the solid and the slurry agitated for three hoursat room temperature and washed three times with deionized water.

The foregoing steps are repeated four times to produce a pentalaminarcomposition containing platinum cations. Treatment of an aqueous slurryof the platinized materials with hydrogen then converts the platinumions into colloidal zero valence platinum metal.

EXAMPLE 7

Zirconyl chloride octahydrate (1.444 g, 4.8 mmol.) is dissolved in 50mLs water and 50% hydrofluoric acid (0.756 g, 19 mmol) are added. Tothis is added a solution of 1 g of1,1'-bisphosphonoethyl-4,4'-bipyridinium dichloride (2.2 mmol) and 0.516g of 85% phosphoric acid (4.5 mmol.) in 50 mLs of water. The reaction isrefluxed for seven days and the white crystalline product is filteredand washed with water, methanol, and acetone and air-dried to yield themixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.5.(O.sub.3 POH)

X-Ray diffraction analysis shows d=14 Å. Infra red analysis is asfollows: (IR (cm-1), 3126, 3056, 1633, 1562, 1499, 1450, 1217, 1055,816, 738, 647, 612, 520, 471). ³¹ P NMR (ppm) are: 3.0, -18.6, -24.5.

EXAMPLE 8

Zirconyl chloride octahydrate (0.21 g, 0.7 mmol.) is dissolved in 10 mLswater and 50% hydrofluoric acid (0.11 g, 2.8 mmol) are added. To this isadded a solution of 0.15 g of 1,1'-bisphosphonoethyl-4,4'-bipyridiniumdichloride (0.35 mmol) and 0.0686 g of 85 % phosphoric acid (0.6 mmol.)in 10 mLs of water. The solution is placed in a 45 mL teflon bomb andthe total volume adjusted to 27 mLs. The bomb is sealed and heated at150° C. for six days to yield the mixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.5.(O.sub.3 POH)

X-Ray diffraction analysis shows d=14 Å. Infra red and ³¹ P NMR (ppm)are identical to those given in Example 7.

EXAMPLE 9

Zirconyl chloride octahydrate (0.36 g, 1.12 mmol.) is dissolved in 10mLs water and 50% hydrofluoric acid (0.179 g, 4.5 mmol) are added. Tothis is added a solution of 0.25 g of1,1'-bisphosphonoethyl-4,4'-bipyridinium dichloride (0.56 mmol) and0.129 g of 85% phosphoric acid (0.11 mmol.) in 50 mLs of 3N hydrochloricacid. The reaction is refluxed for seven days and the white crystallineproduct is filtered and washed with water, methanol, and acetone andair-dried to yield the mixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.5.(O.sub.3 POH)

X-Ray diffraction analysis shows d=18.5 Å. Infra red and ³¹ P NMR (ppm)are identical to those given in Example 7.

EXAMPLE 10

Zirconyl chloride (octahydrate) (0.361 g, 1.12 mmol.) is dissolved in 10mLs water and 0.189 g of 50% hydrofluoric acid (4.8 mmol.) is added.1,1'-Bisphosphonoethyl-bipyridinium dichloride (0.25 g, 0.56 mmol.) andphosphorous acid (0.092 g, 1.12 mmol.) are dissolved in 10 mLs of waterand this solution is added to the aqueous zirconium solution. Thereaction is refluxed for seven days and the white crystalline product isfiltered, washed with water, methanol, and acetone and air-dried toyield the mixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.5.HPO.sub.3

X-Ray diffraction analysis shows d=18.4 Å. Infra red analysis is asfollows: 3126, 3056, 2436, 2358, 2330, 1633, 1555, 1499, 1443, 1386,1210, 1161, 1048, 830, 731, 548. ³¹ P NMR (ppm) are: 5.5, -9.5.

EXAMPLE 11

By following the procedure of Example 10 but utilizing 0.167 (0.38mmol.) of 1,1'-bisphosphonoethyl-bipyridinium dichloride and 0.123 g(1.5 mmol.) of phosphorous acid, there is obtained the mixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.34.(HPO.sub.3).sub.1.32

The material is amorphous. Infra red and ³¹ P NMR (ppm) are identical tothose given in Example 10.

EXAMPLE 12

By following the procedure of Example 10 but utilizing 0.125 (0.28mmol.) of 1,1'-bisphosphonoethyl-bipyridinium dichloride and 0.138 g(1.68 mmol.) of phosphorous acid, there is obtained the mixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.25.(HPO).sub.3).sub.1.50

The material is amorphous. Infra red and ³¹ P NMR (ppm) are identical tothose given in Example 10.

EXAMPLE 13

Zirconyl chloride (octahydrate) (0.151 g, 0.47 mmol.) is dissolved in 10mLs water and 50% hydrofluoric acid (0.079 g, 1.9 mmol.) is added.1,1'-bisphosphonoethyl-bipyridinium dichloride (0.105 g, 0.24 mmol.) andmethyl phosphonic acid (0.045 g, 0.47 mmol.) are dissolved in 10 mLs ofwater and this solution is added to the aqueous zirconium solution. Thereaction is refluxed for seven days and the white crystalline product isfiltered, washed with water, methanol, and acetone, and air-dried toyield the mixed complex:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.5.(CH.sub.3 PO.sub.3).sub.1.0

The material is amorphous. Infra red analysis is as follows: (IR (cm-1),3450, 3133, 3056, 2922, 1633, 1555, 1499, 1450, 1309, 1168, 1027, 823,781, 527).

EXAMPLE 14

In a similar fashion to that described in Example 8, 0.93 mmol. ofzirconyl chloride, 0.34 mmol. of 1,1'-bisphosphonoethyl-bipyridiniumdichloride, and 0.90 mmoles of 3-aminoethylphosphonic acid are heated ina bomb at 150° C. Upon isolation as therein described the amorphousmixed complex exhibits the following IR spectra: (IR (cm-1), 3500, 3126,3055, 1646, 1548, 1499, 1443, 1379, 1154, 1041, 865, 823, 760, 731, 541,499.

EXAMPLE 15

In a similar fashion to that described in either Example 7 or Example 8,zirconyl chloride, 1,1'-bisphosphonoethyl-bipyridinium dichloride, and aphosphorus-containing co-ligand as shown in the following table areallowed to react.

                  TABLE 1                                                         ______________________________________                                        Co-ligand        BPBP*    ZrOCl.sub.2                                         Reagent      mmols.  (mmols.) (mmols.)                                                                             Conditions                               ______________________________________                                        CH.sub.3 PO(OH).sub.2                                                                      0.47    0.23     0.47   Ex. 8:                                                                        150° C.                           CH.sub.3 CH.sub.2 PO(OH).sub.2                                                             1.12    0.56     1.12   Ex. 7                                    CH.sub.3 CH.sub.2 CH.sub.2 PO(OH).sub.2                                                    0.94    0.47     0.94   Ex. 8:                                                                        200° C.                           CH.sub.3 CH.sub.2 CH.sub.2 PO(OH).sub.2                                                    0.83    0.41     0.80   Ex. 8:                                                                        140° C.                           HOCOCH.sub.2 CH.sub.2 PO(OH).sub.2                                                         0.30    0.19     0.15   Ex. 8:                                                                        110° C.                           PhenylPO(OH).sub.2                                                                         1.12    0.56     1.12   Ex. 7                                    ClCH.sub.2 PO(OCH.sub.2 CH.sub.3).sub.2                                                    1.12    0.56     1.12   Ex. 7                                    BenzylPO(OCH.sub.2 CH.sub.3).sub.2                                                         0.70    0.33     0.65   Ex. 7                                    ______________________________________                                         *BPBP = 1,1bisphosphonoethyl-bipyridinium dichloride                     

Thereby produced are mixed complexes of the formula:

    Zr(O.sub.3 PCH.sub.2 CH.sub.2 --bipyridinium--CH.sub.2 CH.sub.2 PO.sub.3 (Cl.sup.-).sub.2).sub.0.5.R.sup.3 PO.sub.3

Data on these products are as follows:

                  TABLE 2                                                         ______________________________________                                        R.sup.3         X-ray        IR Data                                          ______________________________________                                        --CH.sub.3      *            See Ex. 13                                       --CH.sub.2 CH.sub.3                                                                           d = 10.9 Å*                                                                            Spectra I                                        --CH.sub.2 CH.sub.2 CH.sub.3                                                                  d = 11.8 Å*                                                                            Spectra II                                       --CH.sub.2 CH.sub.2 CH.sub.3                                                                  d = 13.6 Å*                                                                            Spectra II                                       --CH.sub.2 CH.sub.2 COOH                                                                      d = 15.4 Å                                                                             Spectra III                                      phenyl          d = 19.7 Å*                                                                            Spectra IV                                       --CH.sub.2 Cl   d = 11 Å*                                                                              Spectra V                                        benzyl          d = 14.5 Å                                                                             Spectra VI                                       ______________________________________                                         *= Peaks present which are attributable to pure metal bisphosphonate.         Spectra I: (IR(cm1), 3507, 3126, 3056, 2978, 2943, 2887, 1640, 1563, 1506     1450, 1393, 1281, 1168, 1048, 872, 830, 738, 541.                             Spectra II: (IR (cm1), 3500, 3126, 3049, 2950, 2866, 1633, 1555, 1499,        1450, 1393, 1246, 1041, 872, 823, 795, 731, 541.                              Spectra III: (IR (cm1), 3500, 2915, 1717, 1633, 1415, 1260, 1027, 816,        752, 534.                                                                     Spectra IV: (IR (cm1), 3500, 3126, 3049, 1633, 1555, 1499, 1443, 1386,        1161, 1055, 865, 823, 749, 731, 710, 541.                                     Spectra V: (IR (cm1), 3500, 3119, 3049, 1633, 1555, 1499, 1443, 1386,         1161, 1055, 865, 823, 759, 731, 710, 541.                                     Spectra VI: (IR (cm1), 3500, 3126, 3056, 1633, 1598, 1492, 1450, 1386,        1253, 1161, 1034, 830, 781, 738, 696, 626, 541, 499.                     

EXAMPLE 16

Zr(O₃ PCH₂ CH₂ --bipyridinium--CH₂ CH₂ PO₃ (Cl⁻)₂)₀.5 (O₃ POH) Thecomplex prepared as in Example 7 (0.05 g) is stirred with 10 mLs of a 10mM aqueous solution of dipotassium platinum tetrachloride at roomtemperature for two days. Over the course of the reaction, the solidchanges from white to yellow. The solid then is isolated by filtration,washed extensively with deionized water, and air dried. The solid issuspended in deionized water and hydrogen gas bubbled through themixture for ten hours. The solid changes from yellow to dark purple. Thesolid is isolated by filtration, washed with deionized water, and airdried to give a brown solid.

EXAMPLE 17

A substrate of gold deposited on a chromium metal film in turn depositedon glass is treated first with 3-aminopropyltriethoxysilane and thenphosphoryl chloride as previously described and then subjected to theprocedure of Example 2 three times to prepare a composition of FormulaIII in which k is 3.

This composition shows a reversible reduction wave at -0.74 V versus asaturated calomel electrode. In water, it shows an irreversiblereduction below -1.4 V versus the same standard electrode.

EXAMPLE 18

Twenty-five milligrams of a composition prepared as set forth in Example6 in 5 mL of 0.1 M disodium ethylenediaminetetraacetic acid as asacrificial reductant in 1 cm² cell is irradiated with a 200 Watt Hg/Xelamp. Levels of hydrogen are measured by gas chromatography. The rate ofhydrogen production over 18 hours of photolysis is 0.07 mL/hr. Passingthe light through a 330 nm cutoff filter (G>330 nm) decreases the rateof hydrogen production by more than an order of magnitude. If the filteris removed the sample photogenerates hydrogen as before. The quantumyield for hydrogen formation (2×moles of H₂ /moles of photons incidentwith G<330 nm) in this system is 0.008.

One preferred class of compositions of the second embodiment consists ofcolloidal particles of Pt and Pd in a porous viologen metal phosphonatematrix. These materials are very different from other Pt+Pd catalysts;the viologen groups make a significant difference in the chemistryinvolved. The oxygen reduction is carried out by reduced viologen, andnot (as is the case in the materials of the DuPont patent) at thecolloid surface, since the rate of reduction of oxygen by reducedviologen is much greater than by the colloidal metal particles. By thenature of the way that the solids are prepared, chloride or bromide"promoters" are unavoidably incorporated. A wide range of differentmaterials were tested. A highly active compound contains a mixture ofbisphosphonic acid and phosphate (i.e. Me(O₃ P--OH)₁ (O₃ P--Z--PO₃)₀.5•nH₂ O•Pt/Pd). Compounds with the phosphate co-ligand where R³ is OHwere found to be between 10 and 100 times more active than compoundswhere R³ was H, CH₃, CH₂ Cl, CH₂ CH₃, or CH₂ CH₂ CH₃. A wide range ofdifferent ratios of Pd:Pt were also tested. The catalysts have beenexamined to determine their uniformity and composition. Samples weredissolved in HF and the resulting solutions analyzed by ICP to get thetotal metal compositions (% by weight of Zr, Pt and Pd, see Table 3).Single particles were analyzed by electron microprobe and found them tohave a uniform Zr:Pt:Pd ratio throughout the particles.

A wide range of different electron accepting groups can be associatedinto this structure that would be amenable to reduction by hydrogen (viacolloidal metal particles) and subsequent use as a catalyst forformation of hydrogen peroxide and other reduced species.

The following are results of side-by-side comparisons of the novelcatalysts of this invention with other Pt+Pd catalysts which wereconducted under identical conditions. (See Table 3). The amount of noblemetal (Pt+Pd) in both the materials of this invention and the othermaterials were analyzed, and then those analyses were used to scale theamount of catalyst in the experiments to have the same amount of noblemetal in each case. The comparisons were performed with mixtures ofhydrogen and oxygen at atmospheric pressure. At increased pressures theconcentration of hydrogen peroxide at steady state (rates of equations 1and 2 above are identical so that the concentration of H₂ O₂ is constantover time) will increase.

                  TABLE 3                                                         ______________________________________                                                      Compound of                                                                   Ex. 24 (below)†                                                                  Other Catalyst‡                            ______________________________________                                        wt % Pt [i.e., Pt/(Pt + Pd)]                                                                  0.1         0.05-0.16                                         [H.sub.2 O.sub.2 ] at steady state (M)                                                        0.14*       0.07                                              (at atmospheric pressure)                                                     Initial turnover # (hr.sup.-1)                                                                30                                                            ______________________________________                                         *Actually 0.22M: In this procedure the solution is brought back up to 10      mL before an aliquot is taken, to compensate for evaporation. The steady      state concentration of peroxide (rate of reaction 1 = rate of reaction 2)     should be constant, regardless of the volume of the sample. Thus when the     sample is diluted the amount of peroxide measured is lower. If the            conditions of the reaction are the same, giving 0.14M peroxide, but the       reaction mixture is not brought to  #10 mL before removing the aliquot th     measured concentration is 0.22M. Thus the steady state concentration of       peroxide was underestimated by roughly 50%.                                   †Zr(O.sub.3 POH)(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.2       CH.sub.2 PO.sub.3)Cl.sup.o Pt.sup.o Pd093                                     ‡The best catalyst disclosed in the DuPont patent (U.S. Pat.       No. 4,832,938                                                            

A number of different materials according to the present invention, bothporous bulk solids and thin films grown on high surface area supports,were prepared and studied.

The bulk solids are prepared by first preparing the layered porous solidof Formula XV; then the halide ions are ion exchanged for polyhalometalanions (such as PtCl₄ ²⁻); and, then the polyhalometal ions are reducedwith hydrogen to give a porous solid with impregnated metal particles.

In carrying out the ion exchange reaction it was found that elevatedtemperatures are needed. At room temperature PtCl₄ ²⁻ is taken uppreferentially over PdCl₄ ²⁻, leading to a solid that is richer in Ptthan the solution it was prepared from. If the ion exchange is carriedout at elevated temperatures the exchange is uniform and the compositionin the solid matches that of the solution exactly.

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl for the followingexamples was prepared as in Examples 7, 8, and 9 above. Various ratiosof platinum and palladium were then incorporated as follows:

EXAMPLE 19

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl °Pt°Pd-58:

170 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl was mixedwith 4.6 ml of PdCl₂ (7.3×10⁻³ M) and 2.8 ml of K₂ PtCl₄ (6.1×10³ M).This mixture was heated to 60° C. with constant stirring for 1 hr. Theyellow powder was filtered and washed three to four times with water.The yellow solid was suspended in water and hydrogen gas was bubbled for1/2 hr at 60° C. The gray/black solid was filtered and washed first withwater and then with ethanol. This solid was then air dried. 0.0072 g ofthe above solid was dissolved in conc. HCl, a few drops of conc. HNO₃,and a few drops of 59% HF the solution was diluted to 100 ml andanalyzed for Zr, Pt, and Pd by ICP. The analysis (ppm) of the solutionare Zr=14.05;Pt=1.01;Pd=0.73

EXAMPLE 20

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt°Pd-32:

260 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl and 3 mlsolution of 0.11M K₂ PdCl₄ and 6.4×10⁻³ M K₂ PtCl₄ was heated to 60° C.for 30 minutes with constant stirring. The yellow solid so obtained wasfiltered and washed several times with water. This solid was resuspendedin water and treated with H₂ gas as mentioned in the first synthesis.0.0136 g of the dried solid was dissolved and analyzed as before, valuesin ppm: Zr=24.72;Pt=0.69;Pd=1.5

EXAMPLE 21

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt°Pd-00:

200 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl was treatedwith 1 ml of 0.11 M K₂ PdCl₄ and 0.18 ml of 1.6×10⁻³ M K₂ PtCl₄ andhydrogenated as mentioned in the previous example. )0.0117 g of thefinal black solid was dissolved in conc. HCl, a few drops of conc. HNO3,and a few drops of 50% HF. This solution was diluted to 25 ml. Theanalysis of the solution is as follows: Zr(ppm)=48.92;Pt=not detected;Pd(ppm)=6.75.

EXAMPLE 22

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt°Pd-30:

200 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl, 1 ml of4.8×10⁻² M K₂ PdCl₄, and 0.275 ml of 4.7×10⁻² M K₂ PtCl₄ was stirred at60° C. for 20 min. The yellow solid so obtained was filtered, washedwith water, and hydrogenated as before. 0.0125 g of the solid wasdissolved as before and diluted to 25 ml for analysis to give Zr=49.91ppm, Pt=2.15 ppm, Pd=4.92 ppm

EXAMPLE 23

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt°PD-11:

500 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl was refluxedfor 6 hrs. with 15 ml of 7.4×10⁻³ M PdCl₂ and 0.99 ml of 5.1×10⁻³ M K₂PtCl₄. The solid was filtered, washed and as before. The hydrogenationof the solid was carried as before except for 1 hr. 0.0172 g of thissolid was dissolved as before and diluted to 25 ml for analysis to giveZr=70.29 ppm;Pt=1.18 ppm;Pd=9.10 ppm

EXAMPLE 24

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt°Pd-093:

500 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl, 15 ml of7.4×10⁻³ M PdCl₂, and 0.99 ml of 5.1×10⁻³ MK₂ PtCl₄ was refluxed for 65hrs. Filtered, washed, and hydrogenated as mentioned in the previousexample. 0.018 g of the solid was dissolved as before and diluted to 25ml for analysis to give Zr=127.98 ppm; Pt-0.78 ppm; Pd=7.72 ppm.

EXAMPLE 25

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt:

200 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl was treatedwith 2 ml of 5.1×10⁻³ M solution of K₂ PtCl₄ at 60° C. for 1 hr. Thesolid was filtered, washed, and hydrogenated as mentioned in theprevious example. 0.0162 g of the solid was used to prepare a 25 mlsolution for the analysis to give Zr=117.9 ppm;Pt=20.01 ppm

EXAMPLE 26

Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pd:

100 mg of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH2PO₃)Cl and 1 ml of6.3×10⁻² M PdCl₂ was treated at 60° C. for 4 hrs. The orange solid wasfiltered, washed, and hydrogenated as before.0.013 1 g of the solid wasdissolved in 25 ml as mentioned above for analysis to give Zr=92.96ppm;Pd=8.54 ppm

The materials are grown on high surface area supports in a multi stepprocess, as described below. Ion exchange can be carried out either asthe film is growing or after it is prepared.

EXAMPLE 27

Synthesis of SiO₂ °Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°:

One gram of silica gel (Selecto,Inc. Cat#162544, lot #216073) was heatedat 200° C. for 1 hr. This was treated with 150 ml of 65 mM ZrOCl₂ at 60°C. for two days. This was followed by a treatment with 150 ml solution,which consists of 20 mM (O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl, 20 mMphosphoric acid, and 60 mM NaCl at 60° C. for 18 hours. These treatmentswere repeated four times. At the end the pale yellow solid was washedwith water and dried.

EXAMPLE 28

SiO₂ °Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl°Pt°Pd-21:

270 mg of SiO₂ °Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂ PO₃)Cl wastreated with 3 ml solution, which was 0.12M in K₂ PdCl₄ and 6.4×10⁻³ Min K₂ PtCl₄ at 60° C. for one hour. Filtered and washed. The solid washydrogenated as mentioned above. 0.0494 g of this solid was dissolvedand in HCl, HNO₃, and 50 HF and diluted to 25 ml. Analyses: Zr=166.8ppm, Pt=2.97 ppm, Pd=10.89 ppm.

EXAMPLE 29

Samples were prepared as described above in the synthesis of eachcompound in Examples 19-28. The metal content of these solutions weredetermined by ICP. The weight percent of viologen was estimated from theZr value, assuming there are 2 Zr atoms per viologen molecule in thesolid. The viologen unit was taken to be C₁₀ H₈ N₂. Resulting data ispresented in Table 4 below.

                  TABLE 4                                                         ______________________________________                                        Elemental analyses of all compounds listed in this disclosure (ICP on         dissolved samples). (% is weight percent)                                                    R                                                              COMPOUND       (obs)  R (theo) % Pt  % Pd % Zr                                ______________________________________                                        Du-D, sample 1 0.02   0.08     0.01  0.38 0                                   DU-D, sample 2 0.08   0.093    0.02  0.23 0                                   DU-F           0.2    0.3      0.05  0.2  0                                   DU-H           0.65   0.7      0.15  0.08 0                                   Zr*PV(POH)*Pd  0      0        0     1.63 17.74                               Zr*PV(POH)*Pt*Pd-005                                                                         0      0.005    not   1.44 17.24                                                              detected                                       Zr*PV(POH)*Pt*Pd-093                                                                         0.092  0.093    0.11  1.07 17.78                               Zr*PV(POH)*Pt*Pd-11                                                                          0.16   0.093    0.32  1.65 16.37                               Zr*PV(POH)*Pt*Pd-14                                                                          0.14   0.09     2.42  1.48 18.29                               Zr*PV(POH)*Pt*Pd-30                                                                          0.29   0.14     0.43  1.17 18.71                               Zr*PV(POH)*Pt*Pd-32                                                                          0.32   0.093    0.51  1.1  18.18                               Zr*PV(POH)*Pt*Pd-58                                                                          0.58   0.49     1.4   1.01 19.51                               Zr*PV(POH)*Pt  1      1        3.09  0    18.19                               Zr*PV(POH)*Pd + PtCl.sub.4                                                                   0.85   Unknown  3.86  0.66 46.56                               Zr*PV*Pt       1      1        4.3   0    12.35                               Zr*PV(PH)*Pt   1      1        7.96  0    14.87                               Zr*PV(POH)*Pt + PdCl.sub.4                                                                   0.6    Unknown  2.35  1.57 16.55                               SiO.sub.2 *Zr*PV(POH)*Pt*Pd-11                                                               .11    0.093    0.1   0.78 8.06                                SiO.sub.2 *Zr*PV(POH)*Pt*Pd-21                                                               .21    0.093    0.15  0.55 8.7                                 SiO.sub.2 *Zr*PV(POH)*Pt*Pd-27                                                               .27    0.093    0.35  0.9  2.67                                ______________________________________                                         Definitions for Table 1.:                                                     DUD: DuPont's U.S. Pat. No. 4,832,938 Table 1 A prep D; DUF: DuPont's U.S     Pat. No. 4,832,938 Table 1 A prep.F; DUH: DuPont's U.S. Pat. No. 4,832,93     Table 1 A prep.H.                                                             Zr*PV(POH) = Zr(O.sub.3 POH)(O.sub.3 PCH.sub.2 CH.sub.2                       bipyridiniumCH.sub.2 CH.sub.2 PO.sub.3)Cl                                     Zr*PV(PH) = Zr(O.sub.3 PH)(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.     CH.sub.2 PO.sub.3)Cl                                                          Zr*PV = Zr(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.2 CH.sub.2           PO.sub.3)Cl                                                                   R = Pt/(Pt + Pd) (wt./wt.)                                                    R(obs.) = The ratio calculated from the analysis of Pt and Pd by ICP.         R(theo) = The ratio calculated from the initial concentrations of Pt and      Pd in the reacting solution.                                             

HYDROGEN PEROXIDE FORMATION:

The materials of the present invention can be used as catalysts for theproduction of hydrogen peroxide. The process comprises treating anaqueous suspension of the catalyst with a source of oxygen and a sourceof hydrogen. Sources for oxygen include pure oxygen, air, ozone or anynitrogen oxide. The suspension can also contain acids or bases tocontrol the pH of the system.

EXAMPLE 30

An amount of each of the catalysts was placed in a 50 mL plastic tube.10 mL of 0.15 mM solution of acetanilide in 0.1 M HCl was added to eachtube, and it was sealed with a rubber septum. A mixture of oxygen andhydrogen was bubbled through the suspension. In some cases air was usedrather than O₂. At sequential time intervals, starting at 1 hour (up toabout 28 hours) the loss of solution volume due to evaporation was madeup by the addition of 0.15 mM solution of acetanilide in 0.1 M HCl andan amount of reaction mixture was withdrawn and diluted to 5 mL withtitanium sulfate solution previously prepared in sulfuric acid. Theabsorbance of the solutions was recorded at 410 nm. The colorimetricassays have been checked by titration of the same solutions with KMnO₄and shown to be very accurate. Table 4 shows the elemental analyses ofcompounds synthesized and/or used. The data shows the catalyticproperties of the compounds in the production of hydrogen peroxide atvarious stages and under various conditions including different ratiosof Pt to Pd and at a number of pHs.

The data listed in Table 5 represents H₂ O₂ production for two preferredmaterials according to the present invention and some other catalysts.Table 6 shows similar test data for other compounds according to thepresent invention and other compounds. Table 7 shows data collected forseveral catalysts having different ratios of Pt to Pd. Table 8 showsdata at a number of different pHs.

TABLE 5 Hydrogen peroxide formation, pH=1 atm. The amount of catalystsused in each experiment was adjusted to give a constant number of molesof Pt+Pt in each experiment.

                  TABLE 5                                                         ______________________________________                                                               Amount             Initial                                                    of                 Turn-                                             Gas Ratio                                                                              Catalyst                                                                              Time |H.sub.2 O.sub.2 |                                                over                                Compound      H2:O2    (mg)    (hrs.)                                                                             (mM)  #                                   ______________________________________                                        Zr.PV(POH).Pt.Pd-093                                                                        1:1      22      1    12    10.8                                                               2.5  28                                                                       5    43                                                                       7    44                                                                       8.5  50                                                                       24   99                                                      1:5      23      1.3  33    29.4                                                               2.3  51                                                                       4.6  71                                                                       6.3  79                                                                       8.3  80                                                                       24   140                                                      1:10    22      1    10    8.8                                                                2.2  21                                                                       3.5  29                                                                       5.0  37                                                                       7.3  48                                                                       22   101                                                      1:20    24      1    11    10                                                                 2.4  28                                                                       4.2  39                                                                       5.7  53                                                                       8.2  71                                                       1:40    23      1    2.4   2.4                                                                3.5  28                                                                       5.5  45                                                                       7.5  54                                                                       23   88                                                                       26   79                                                                       28   76                                        SiO.sub.2.Zr.PV(POH).Pt.Pd-21                                                               1:5      44      1    10    10                                                                 2.5  22                                                                       4    31                                                                       6.5  33                                                                       8.3  33                                                                       9    33                                        DU-D, Sample 2                                                                              1:5      118     1    16    16                                                                 2.9  31                                                                       3.9  38                                                                       5.9  49                                                                       7.9  58                                                                       23   77                                        DU-H          1:5      128     1.1  16    16                                                                 2.5  24                                                                       4    32                                                                       7.3  36                                                                       23   50                                                                       26   50                                                                       28   50                                        DU-F          1:5      122     1    10    10                                                                 2.3  19                                                                       4    30                                                                       6    44                                                                       9    58                                                                       24   46                                        ______________________________________                                         DU-D: DuPont's U.S. Pat. No. 4,832,938 Table 1 A prep D.                      DUF: DuPont's U.S. Pat. No. 4,832,938 Table 1 A prep.F.                       DUH: DuPont's U.S. Pat. No. 4,832,938 Table 1 A prep.H.                       Zr*PV(POH) = Zr(O.sub.3 POH)(O.sub.3 PCH.sub.2 CH.sub.2                       bipyridiniumCH.sub.2 CH.sub.2 PO.sub.3)Cl                                     Zr*PV(PH) = Zr(O.sub.3 PH)(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.     CH.sub.2 PO.sub.3)Cl                                                          Zr*PV = Zr(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.2 CH.sub.2           PO.sub.3)Cl                                                                   PdPt-# refers to Pt/(Pt + Pd) (wt./wt.)                                  

                  TABLE 6                                                         ______________________________________                                        Comparison of DuPont catalysts and novel catalysts according to               the present invention using an H.sub.2 :O.sub.2 ratio of 2:1 (O.sub.2         from air)                                                                     at pH = 1. The amount of catalyst used in each experiment was                 adjusted to give a constant number of moles of Pd + Pt in each                experiment.                                                                                           H.sub.2 O.sub.2                                                                        H.sub.2 O.sub.2                                             Quantity (mM) at  (mM) at                                                                              Mole                                  COMPOUND       (mg)     18 hours 45 hours                                                                             % Pd                                  ______________________________________                                        DU-D           152      4.6      1.0    0.545                                 DU-F           246      2.2      0.5    0.464                                 DU-H           262      4.6      4.5    0.200                                 Zr.PV(POH)Pt.Pd-58                                                                           25       12.5     2.6    0.238                                 Zr.PV(POH)Pt.Pd-32                                                                           38       22.5     15.1   0.394                                 Zr.PV(POH)Pt.Pd-30                                                                           42       18.3     9.0    0.386                                 Zr.PV(POH)Pt.Pd-00                                                                           43       13.7     10.1   0.584                                 SiO.sub.2.Zr.PV(POH)Pt.Pd-27                                                                 49       3.5      2.6    0.416                                 Zr.PV.Pt       25       0.5                                                   Zr.PV(PH).Pt   40       0.6                                                   Zr.PV(POH).Pt  30       5.5                                                   ______________________________________                                         DU-D: DuPont's Patent U.S. Pat. No. 4,832,938 Table 1 A prep D.               DUF: DuPont's Patent U.S. Pat. No. 4,832,938 Table 1 A prep. F.               DUH: DuPont's Patent U.S. Pat. No. 4,832,938 Table 1 A prep. H.               Zr*PV(POH) = Zr(O.sub.3 POH)(O.sub.3 PCH.sub.2 CH.sub.2                       bipyridiniumCH.sub.2 CH.sub.2 PO.sub.3)Cl                                     Zr*PV(PH) = Zr(O.sub.3 PH)(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.     CH.sub.2 PO.sub.3)Cl                                                          Zr*PV = Zr(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.2 CH.sub.2           PO.sub.3)Cl                                                                   PdPt-# refers to Pt/(Pt + Pd) (wt./wt.)                                  

                  TABLE 7                                                         ______________________________________                                        H.sub.2 O.sub.2 production from catalysts with different amounts of Pt        (different                                                                    R values) 2:1 mixture to H.sub.2 :O.sub.2 (air was used as an oxygen          source) 1 atm,                                                                pH = 1                                                                                       Quantity    Time   H.sub.2 O.sub.2                             COMPOUND       (mg)        (hrs.) (mM)                                        ______________________________________                                        Zr.PV(POH).Pt.Pd-005                                                                         28          1      2.2                                                                    23     2.5                                                                    27.5   2.5                                                                    30     2.7                                         Zr.PV(POH).Pt.Pd-11                                                                          29          1      2.8                                                                    23     4.5                                                                    27.5   5.8                                                                    30     8.9                                         Zr.PV(POH).Pt.Pd-093                                                                         56          1      4.2                                                                    7      7.7                                         Zr.PV(POH).Pt.Pd-32                                                                          31          1      2.5                                                                    23     4.9                                                                    27.5   5.1                                                                    30     5.2                                         Zr.PV(POH).Pt.Pd-58                                                                          30          1      2.2                                                                    23     3                                                                      27.5   2.9                                                                    30     2.9                                         ______________________________________                                         Zr*PV(POH) = Zr(O.sub.3 POH)(O.sub.3 PCH.sub.2 CH.sub.2                       bipyridiniumCH.sub.2 CH.sub.2 PO.sub.3)Cl                                     PdPt-# refers to Pt/(Pt + Pd) (wt./wt.)                                  

                  TABLE 8                                                         ______________________________________                                        Altering pH with HCl, H.sub.2 :O.sub.2 = 1:5, 1 atm using                     Zr(O.sub.3 POH)(O.sub.3 PCH.sub.2 CH.sub.2 bipyridiniumCH.sub.2 CH.sub.2      PO.sub.3)Cl.Pt.Pd-093.                                                               Quantity of                                                                             Time       H.sub.2 O.sub.2                                                                    Turnover #                                   pH     Cmpd. (mg)                                                                              (hrs.)     (mM) (total)                                      ______________________________________                                        1      23        1.3        33   29                                                            2.3        51                                                                 4.6        71                                                                 6.3        79                                                                 8.3        80                                                                 24         140  125                                          2      22        1.3        18   17                                                            3.3        68                                                                 4.8        78                                                                 5.8        80                                                                 6.8        89   85                                           3      23        1.0        17   16                                                            2.8        23                                                                 4.0        23   21                                                            6.3        19                                                ______________________________________                                    

The above examples all involved atmospheric pressure reactions. Twoparameters are important in this regard, those are the initial rate ofhydrogen peroxide formation and the steady state concentration ofhydrogen peroxide. The steady state concentration indicates theconcentration at which the system is making water from peroxide at thesame rate that peroxide is being formed, while the initial rate is anindication of the rate of hydrogen peroxide formation. The best steadystate value observed was 140 mM (Table 5). At steady state the rate ofoxygen reduction (equation 3) and hydrogen peroxide reduction (equation4) are equal, so that the concentration of hydrogen peroxide isconstant. The initial rate of the reaction in these experiments is 30turnovers per hour (based on the moles of viologen present in thesystem). These experiments were carried out with a catalyst which has anR of 0.093 and a mixture of 1:5 of H₂ :O₂. The best DuPont catalyst(DU-D) treated in an identical manner produced only 77 mM hydrogenperoxide at steady state. As the mixture of H₂ and O₂ is made richer inoxygen (i.e. H₂ :O₂ =1:10) the amount of hydrogen peroxide produceddecreases.

Other catalysts loose a good fraction of their activity very quickly. Totest this we took one sample of the catalyst and used it in severalsuccessive experiments. The results are shown in Table 9. To minimizehazards, a mixture of hydrogen and air was used in these experiments, sothat the steady state values for the peroxide concentration are lowrelative to the numbers quoted above. The first three experiments showvery similar level of peroxide production. The fourth experiment, showsa lower level of activity than the first three. This level of activityis still much higher than that observed for the DuPont catalyst underidentical conditions. Elemental analysis shows that after the fourthcycle the weight % of Pt and Pd have gone up slightly, while the amountof Zr has gone down. This observation suggests that the decrease inactivity has to do with partial dissolution of the metal phosphonate.

                  TABLE 9                                                         ______________________________________                                        Hydrogen Peroxide formulation using Zr.PV(POH).Pt.Pd-093, pH = 1,             H.sub.2 :O.sub.2 = 2:1 (air used as O.sub.2 source), pressure = 1 atm.        Cycle # time (hrs.) [H.sub.2 O.sub.2 ] (mM)                                                                  total turnovers                                ______________________________________                                        1st     1           4.2        1.5                                                    2.5         4.3                                                               5           6.1                                                               7           7.7        2.8                                                    25          4.6                                                       2nd     1           4.5        2.6                                                    2.8         9.8        5.6                                                    5.1         7.9                                                               6.8         8                                                         3rd     1           7.1        4.0                                                    5           10.7       6.1                                                    7           3.6                                                       4th     1.2         4.2        2.4                                                    3           4.1                                                               6           4.5        2.6                                            ______________________________________                                    

EXAMPLE 31

High Pressure Hydrogen Peroxide Formation:

A number of experiments were performed with various combinations of gaspressures (H₂, O₂, N₂) in a 70 ml pressure vessel. Five mls of 0.1 M HCland 25 milligrams of Zr(O₃ POH)(O₃ PCH₂ CH₂ bipyridiniumCH₂ CH₂pO₃)Cl*Pt*Pd-14 were added to the vessel. A mixture of oxygen, hydrogen,and nitrogen at the prescribed pressures was added to the vessel. Thereactions were allowed to proceed for various times. (TABLE 10). The H₂O₂ concentrations are similar to those obtained in experiments atatmospheric pressure (see above). The data shows that an increase ineither reactor vessel volume or an increase in pressure would yieldhigher H₂ O₂ concentrations, i.e., if P_(H2) and P_(O2) were increasedby a factor of 5 the results would be one molar H₂ O₂ (see e.g., example2 in Table 10).

                  TABLE 10                                                        ______________________________________                                                                                    Yield of                                                                      H.sub.2 O.sub.2                        |H.sub.2 O.sub.2 |                                                   Total                         relative to                       Time final    pressure                                                                              P.sub.O2                                                                           P.sub.H2                                                                           P.sub.N2                                                                           Moles H.sub.2                                                                        H.sub.2 in                        (hrs)                                                                              (moles/L)                                                                              (psi)   (psi)                                                                              (psi)                                                                              (psi)                                                                              in system                                                                            system                            ______________________________________                                        15   0.143    175     100  15   60   0.0029 25%                               23   0.214    175     100  15   60   0.0029 37%                                48†                                                                        0.410    175     100  15   60                                            18   0.084    150     120   6   24   0.0011 38%                               13   0.062    150     120   6   24   0.0011 28%                               ______________________________________                                         †After 24 hours the system was vented and a fresh charge of the        same gas mixture was added, then allowed to react for another 24 hours.  

EXAMPLE 32

Synthesis of phosphonate derivatized Polymer template:

Diethyl-4-bromobutylphosphonate was made by the Michealis-ArbuzovRearrangement of Br(CH₂)₄ Br with triethyl phosphite. 1,4-dibromobutane(21.5 g, 100 mmol) and triethylphosphite (6.65 g, 40 mmol ) were heatedto 150° C. for 6 hours. Unreacted 1,4-dibromobutane was removed byvacuum distillation.

Poly(4-vinylpyridine) (PVP) was alkylated with diethyl 4-bromobutylphosphonate to give polymers (PVP-C₄ P). PVP (1 g, 9.5 mmol) wasdissolved in 60 mL N, N-dimethyl formamide (DMF) with 1.48 g (5.4 mmol)of diethyl-4-bromobutylphosphonate. The mixture was stirred at 60° C.for two hours, and DMF was removed under vacuum. The remaining solid waswashed with a 1:4 (v:v) mixture of methanol and diethyl ether, and thenrefluxed in ether for two hours. The solid sample was filtered anddried. The dried sample was then dissolved in 30 mL methylene chloride,12 g of bromotrimethylsilane was added and the mixture was stirred for 6hours under an Ar atmosphere. H₂ O (80 mL) was added and the solutionwas stirred one more hour. The water phase was separated, and removedunder vacuum to get yellow-brown solid (PVP-C₄ P). CHN analysis ofPVP-C₄ P gave C: 55.76, H: 6.67, N: 8.20. This analysis is consistentwith 25% of the pyridyl groups being alkylated. [C₇ H₇ N]₃ [C₁₁ H₁₇ NO₃PBr]*3H₂ O would give a CHN analysis of C: 55.57, H: 6.41, N: 8.10. TheNMR spectra of PVP-C₄ P consists of relatively broad lines, due to thepolymeric nature of the material. Three broad appear in the 1H NMRspectrum in d6-DMSO/D₂ O at 8.2, 6.6 and 1.6 ppm, with integratedintensities of 1,1, and 2.4. This ratio is consistent with the 25%derivitization if the two downfield peaks are assigned topyridyl/pyridinium resonances and the peak at 1.6 ppm is assigned to allof the CH₂ groups except the one bound to nitrogen (based on modelcompounds the latter peak is expected to fall under HDO), since thisshould give a ratio of 1:1:2.3.

EXAMPLE 33

Platinum colloids were prepared via reduction of hexachloroplatinatesolution by sodium citrate. The reduction was similar to that describedby Brugger, et. al., except that the temperature was held at 90° C. inorder to get uniform particle size (P. Brugger, P. Cuendet, M. Gatzel,J. Am. Chem. Soc., (1981), 103, page 2923.) K₂ PtCl₆ (40 mg) wasdissolved in 300 mL distilled water and the solution was heated to 90°C. An aqueous solution of sodium citrate (30 mL, 1% weight percentsodium citrate) was added and the solution stirred for 3 hours. Afterthe colloid suspension was cooled to room temperature, Amberlite-MB-1exchange resin was added and the mixture was stirred to remove theexcess citrate until the conductivity of the solution was less than 5S/cm.

EXAMPLE 34

Growth of zirconium viologen-bisphosphonate (ZrVP) on PVP-C₄ P:

Polymer PVP-C₄ P (5 mg) was dissolved in 50 mL of the Pt colloidsuspension described above. The weight ratio of Pt: polymer is 1:2.5.After the mixture was shaken for one hour to reach equilibrium, 0.3 gmof ZrOCl₂ •8H₂ O was dissolved in the PVP-C₄ P/Pt suspension. Themixture was shaken at room temperature overnight in order to completethe reaction of Zr⁴⁺ ions with phosphonate groups of the polymer. Themixture was then dialyzed against distilled water to remove free ions.The molecular weight cut of the dialysis tube used here was12,000-15,000.

Dialysis was carried out until conductivity of the water was less than 5mS/cm. The suspension was poured back to a flask, 0.04 g viologenbisphosphonic acid was added and the mixture was shaken at 60° C.overnight, a similar dialysis process was carried out to a conductivityof less than 5 mS/cm. The zirconium and bisphosphonate treatments wererepeatedly performed up to five times in order to grow multiple layersof the ZrVP materials.

EXAMPLE 35

Photochemical Hydrogen Generation:

Photochemical hydrogen generation was carried out by irradiating samplesof the polymer templated ZrVP on Pt colloids (Example 34) in EDTAsolutions. The suspension was held in a 1 cm square cell kept at 20° C.throughout the photochemical experiment. A mixture of 4 mL of the samplesuspension and 1 mL of 0.1 M NaEDTA (sacrificial reducing agent) werethoroughly degassed by bubbling N₂ through the suspension prior tophotolysis. The sample was then irradiated with a 200 Watt Hg/Xe arclamp. Levels of hydrogen were measured by GC.

Photolysis of a suspension sample with 11 mg ZrPV(Cl) in 0.05 M NaEDTAby a 200-w Hg/Xe lamp leads to a hydrogen production rate 0.25 mL/hr forthe first hour. EDTA is used as a sacrificial reductant to turn thesystem over. The rate of hydrogen production gradually decrease onlonger irradiation time. This is similar to that on multi layer thinfilms grown on silica surface.

Passing the light through a 260 nm cutoff filter decreases the rate ofhydrogen production by about 50%, but produces about 20% more hydrogenin longer period of time. The wave length dependence for photoproductionof hydrogen in this system correlates well with that observed in formingcharge-separated state in both microcrystalline and thin film sample ofZrPV(Cl).

EXAMPLE 36

Sample and Substrate Preparation.

Polymer PVP-C₄ P (molecular weight=100,000) was synthesized frompoly(4-vinylpyridine) and diethyl,4-bromobutyl-phosphonate by the methoddescribed in Example 32. H₂ O₃ PCH₂ CH₂ (bipyridinium)CH₂ CH₂ PO₃ H₂ Cl₂(V2P,) was prepared as described in Example 1. Single-crystal polishedsilicon wafers and microscopic fused silica (quartz) slides (˜1×3 cm²)and 0.05-0.1 mm thick gold, platinum and palladium foil (˜1×0.5 cm²)were each used as substrates. They were cleaned before use with amixture of concentrated H₂ SO₄ and 30% H₂ O₂ (v/v 3:1), rinsedthoroughly with distilled water and heated at 500° C. overnight toprovide a dehydroxylated surface.

Surface Initialization Procedure.

A silicon wafer, quartz slide or metal foil strip was dipped into anaqueous 0.5% (w/w) solution of PVP-C₄ P. After 5 minutes, the slide wasremoved from the solution and dried by blowing pure N₂. A thin layer of80 mM solution of ZrOCl₂ was applied to the surface of the slide toachieve the cross-linking of phosphonic acid residues of polymer and thefilm was air-dried. To make sure that the polymer was fully cross-linkedwith Zr⁴⁺ ions, the process was repeated twice. The slide was thenwashed with distilled water to remove extra ions from surface.

Film Growth.

Multilayers of ZrPV(Cl) compound were produced on the zirconium richsurfaces by repeated dipping of the initialized substrate in 10 mM V2Paqueous solution at 80° C. for 4 hours (step 1), then in 60 mM ZrOCl₂aqueous solution at room temperature for 2 hours (step 2). The surfacewas thoroughly rinsed with distilled water between dippings (step 3).Steps 1-3 constituted one cycle of treatment. Various films were made byrepeating up to 15 cycles. In the last cycle step 2 was usually omitted.

EXAMPLE 37

Atomic force microscopic (AFM) images were obtained with NanoScope IIIScanning Probe Microscope (Digital Instruments). Surface was imaged in atapping mode with silicon cantilevers (typical F_(o) 320-360 kHz). AFMimages (0.5×0.5 μm2) of the samples reveal their finer features anddemonstrate that the structure and thickness of the films prepared inthe same way depends on the nature of the substrate. All of the samplesshowed a significant increase in RMS roughness on film growth.

Examination of the AFM images shows that in all case the materialsgrowing on the surface consist of microcrystallites. It is in contrastto the growth of Zn and Cu alkanebisphosphonate mutlilayer films (Yang,H. C., K. Aoki, H. -G,. Hong, D. D. Sackett, M. F. Arendt, S. -L. Yau,C. M. Bell, T. E. Mallouk J. Am. Chem. Soc. 1993, 115, 11855-11862.)which results in the smoothing of surface roughness. The crystals aresmaller in the case of quartz and silicon substrates and larger in thecase of metals. There seems to be no direct correlation between theoverall roughness of the film and the crystal size, as well as betweenthe roughness of the bare substrate and of the film on it. The films onquartz consist of small crystals uniformly distributed on the surface.Films on gold and platinum are made up of somewhat larger crystals thanthose on quartz, but they are still uniformly distributed on gold andtend to aggregate into larger clusters on platinum. Growth of films onPd leads to large crystals, which appear clustered into even largerislands. In contrast, films on silicon consist of very small particles,which also cluster into large islands. No differences were observed inthe AFM images of untreated and PVP-C₄ P treated substrates.

EXAMPLE 38

Cyclic voltammograms (CV) were registered at Au, Pt and Pd electrodes(working surface area ˜0.3 cm²) covered with ZrPV(Cl) films as describedabove in Examples 36-37. PAR Potentiostat/Galvanostst Model 283 wasused. A counter electrode (Pt wire) was separated from the workingaqueous 0.1 M KCl solution by a porous glass frit. The reference was asaturated calomel electrode (SCE). Oxygen was removed from the workingsolution by bubbling with argon gas of high purity.

Cyclic voltammograms of the ZrPV(Cl) films at the Au, Pt and Pdelectrodes show broad peaks with reduction potentials (E^(o) _(surf)=(E_(p),c +E_(p),a)/2, where E_(p),c and E_(p),a are the cathodic andanodic peak potentials, respectively) close to -0.77 V, withpeak-to-peak separations (₋₋ E) of 120-200 mV. ₋₋ E is slightly affectedby the number of treatments on gold and platinum but shows no change forpalladium. This large ₋₋ E increasing as the experimental time scale isshortened (at higher potential scan rates) indicates the kineticlimitations for charge transfer which are more serious for anodicprocesses and for Pt and Pd electrodes.

Integration of the reduction peaks at the cyclic voltammograms confirmthat the amount of ZrPV(Cl) accumulated at the surface after the samenumber of treatments is different for different substrates. Much morematerial is being accumulated at Pt and Pd than at Au. These results areconsistent with the AFM data indicating that films at Pt and Pd are morerough than at Au. Estimates based on the integrals obtained from thecyclic voltammograms indicate that every cycle of treatment results notin a single layer coating but adds 3-6 layers depending on substrate.

The E^(o) _(surf) values are 100 mV more negative than E^(o) for theone-electron reduction of V2P in aqueous solution which we found to be-0.67 V (₋₋ E=70 mV), which is close to the redox potential reported forthe methylviologen dication/cation radical redox couple (-0.69 V). The100 mV shift of E^(o) _(surf) to the more negative values in films ascompared to V2P in solution is not significantly affected by the numberof times the substrate is treated with the Zr⁴⁺ and viologenbisphosphonate.

EXAMPLE 39

Blue color due to photochemical charge separation is observed on thelayered ZrPV(Cl) with polysoap template, if the sample is photolyzedwith a 200 w Hg/Xe lamp in vacuum or under N₂. Five minute photolysisleads to the formation of both reduced viologen monomer and dimmer onthe irradiated sample. Electron spectra show the decreasing band of 270nm, and appearance of bands at 405, 605 nm and 380, 540 nm, which arecorrespond to monomer and dimmer respectively. The electronic spectra ofthe ZrPV(Cl) with polysoap template, as well as the air sensitivity ofthe photoreduced sample suggest that this multilayered compound is notas tightly packed a, microcrystalline samples of ZrPV(Cl).

Treating of a photoreduced suspension sample of layered ZrPV(Cl) withtemplate with air leads to complete bleaching within a matter ofseconds, while the microcrystalline samples require hours to days.Oxygen appears to freely diffuse through the more open lattice of thecompound. This is probably related to the flexible blanket-like featureof the materials with template.

EXAMPLE 40

Synthesis of 1,4Bis(4phosphonobutylamino)benzene (PAPD).

(H_(2O) ₃ P--(CH₂)₄ --NHC₆ H₄ NH--(CH₂)₄ --PO₃ H₂).

5.0 g. (0.046 moles) of p-phenylendiamine and 15.6 g. (0.114) of diethyl4-bromobutyl phosphonate were refluxed in 50 mL of THF in the presenceof 1.56 g. of NaH for 2 days. After cooling, 50 mL of H₂ O were slowlyadded to the reaction mixture. The solution was extracted three timeswith 100 mL portions of CHCl₃. TLC showed the desired product was in theCHCl₃ layer. Decolorizing charcoal was added to the CHCl₃ solution andstirred for 1 hr then filtered. The CHCl₃ solution was taken to drynessleaving a brown oil. ¹ H NMR (D₂ O), 6.9(4H, s), 3.1(4H, t), 1.5(12H, m)ppm. Mass Spectrum: E.I., M⁺¹ meas.=492, M⁺¹ theor.=492; majorfragments: 446, 354, 193, 137, 125. The ester was hydrolyzed to the acidby refluxing in 6 M HCl for two days. The acid was precipitated fromthis solution by the addition of acetone.

EXAMPLE 41

Synthesis of viologen bisphosphonic acid salts[N,N'-bis(2-phosphonoethyl)-4,4'-bipyridine dihalide] (PV(X)):

(H₂ O₃ P--(CH₂)₂ --4,4'--bipyridinium--(CH₂)₂ --PO₃ H₂).

The viologen dichloride salt was prepared by reacting 1.2 g. (6.0mmoles) of diethyl (2-chloroethyl) phosphonate with 0.47 g. (3.0 mmoles)of 4,4'-bipyridine in 120 mL of H₂ O at 110° C. for 40 hours. The esterwas converted to the acid by refluxing in 6M HCl. The viologen dibromidesalt was prepared as above except diethyl-2-bromoethylphosphonate wasused. The ester was dried under vacuum then converted to the acid byovernight stirring with a three fold excess of bromotrimethyl silane indry acetonitrile followed by the addition of water. The viologendiiodide salt was prepared by adding AgPF₆ to a solution of the viologendichloride salt to precipitate AgCl. When the viologendihexafluorophosphate salt was isolated, an excess of KI was added tothe solution. The resulting reddish-brown solid was isolated byfiltration. All viologen salts were purified by dissolving in a minimumvolume of water and precipitated by the slow addition of isopropylalcohol. ¹ H NMR of all salts, (D₂ O), 9.1(4H, d), 8.5(4H, d), 4.2(4H,m), 2.0(4H, m) ppm.

EXAMPLE 42

Synthesis of 4,4'-bis(2-phosphonoethyl) biphenyl (EPB):

(H₂ O₃ P--(CH₂)₂ -(4,4'-biphenyl)-(CH₂)₂ --PO₃ H₂).

In a dry glass pressure tube were added 3.8 g. (9.4 mmol)diiodobiphenyl, 3.23 g. (20 mmol) diethyl vinylphosphonate, 0.05 g. (0.2mmol) palladium acetate and 0.23 g. (0.7 mmol) tritolylphosphinedissolved in 20 mL dry triethylamine and 30 mL dry toluene. Mixture waspurged with Ar for 10 min then closed. Reaction was heated to 110° C.with stirring for 24 hrs. Approximate yield of 4,4'-bis(diethyl vinylphosphonate) biphenyl was 30%. ¹ H NMR (DMSO), 7.8 (8H, m), 7.4 (2H, d),6.5 (2H, t), 4.0 (8H, m), 1.2 (12H, t) ppm. Mass Spectrum: E.I., M⁺¹meas.=478, M⁺¹ theor.=478; major fragments: 369, 341, 313, 231, 202.This intermediate was hydrogenated with Pd/C in methanol. To the esterwere added 20 mL dry CH₂ Cl₂ and 1 mL bromotrimethyl silane. After theaddition of water and separation with ether, the acid was isolated. ¹ HNMR (CDCl₃), 7.4(8H, d), 2.9(4H, m), 2.1(4H, m) ppm.

EXAMPLE 43

Synthesis of N,N'-bis(2-phosphonoethyl)-4,4'-bis(4-vinyl pyridine)biphenyl dichloride (VPB):

(H₂ O₃ P--(CH₂)₂ NC₅ H₄ -CH═CH--(4,4'-biphenyl )--CH═CH--C₅ H₄ N--(CH₂)₂--PO₃ H₂).

In a dry glass pressure tube were added 1.04 g. (2.6 mmol)diiodobiphenyl, 3.0 mL (27 mmol) vinyl pyridine, 0.09 g. (0.36 mmol)palladium acetate and 0.2 g. (0.6 mmol) tritolylphosphine dissolved in 8mL dry triethylamine and 20 mL dry acetonitrile. Mixture was purged withAr for 15 min then closed. Reaction was heated to 110° C. with stirringfor 48 hrs. Approximate yield of 4,4'-bis(4-vinyl pyridine) biphenyl was30%. ¹ H NMR (CDCl₃), 8.9 (4H, d), 8.2 (4H, d), 8.1 (4H, d), 7.9 (4H,d), 7.6 (4H, d) ppm. Mass Spectrum: E.I., M⁺¹ meas.=360, M⁺¹ theor.=360;major fragments: 266, 180, 91. 0.3 g. (0.83 mmol) of this were combinedwith 0.5 g. (2.0 mmol) diethyl-2-bromoethyl phosphonate in a roundbottom flask and dissolved in 10 mL DMF. Mixture was heated at 90° C.for 16 hrs until a yellow precipitate was observed. DMF was vacuumdistilled and the yellow ester was obtained. To the ester were added 10mL dry CH₂ CH₂ and 1 mL bromotrimethyl silane. Mixture was stirred for12 hrs then H₂ O was added causing am orange precipitate. Solid wasisolated and recrystallized from H₂ O by the slow addition of coldmethanol. NMR showed the disappearance of the ester peaks indicating theacid was formed. ¹ H NMR (DMSO), 8.42 (4H, d), 8.22 (4H, d), 7.55 (8H,rn), 7.04 (4H, d), 4.26 (4H, t), 1.41 (4H, t) ppm.

EXAMPLE 44

Preparation of Au/4(ZrAV2P) photoelectrode:

Gold foil (0.1 mm thick) was cut into pieces 2×50 mm2 and cleaned in aconcentrated HNO3 for 10 min, then thoroughly rinsed with distilledwater and 100% ethanol. Self-assembled films of(3-mercaptopropyl)trimethoxysilane (3-MPT) were formed by immersion ofAu foil into solution of 20 mM 3-MPT in 100% ethanol for 2 hours at roomtemperature. (See e.g., W. R. Thompson, J. E. Pemberton, Thin Sol-GelSilica Films on (3-Mercaptopropyl) trimethoxysilane modified Ag and Auelectrodes, Chem. Mater. 7, 130-136 (1995)). Then Au was rinsed with100% ethanol and allowed to air-dry. Hydrolysis of the 3-MPT modifiedsurface was then achieved by immersion into an aqueous 0.1 M solution ofHCl for 12 hours at room temperature. The surface was zirconated bydipping the foil into 60 mM ZrOCl2 aqueous solution for 2 hours at roomtemperature.

AV2P (H₂ O₃ P--(CH₂)--C₆ H₄ --NC₅ H₄ --C₅ H₄ N--C₆ H₄ --(CH₂)--PO₃ H₂)was synthesized using standard literature procedures. The ZrAV2P filmwas grown by alternate treatment in 10 mM AV2P solution at 80° C. for 4hours and then in 60 mM ZrOCl2 aqueous solution at room temperature for2 hours. These 2 steps were each repeated 4 times (4 cycles ofdeposition).

EXAMPLE 45

Photochemistry of Film of Example 44

Photoelectrochemical measurements were performed in a quartz cellcontaining 0.1 M NaClO4 (supporting electrolyte) and 10-2 M Eu(NO3)3(electron acceptor). Dark currents and photocurrents were measured withPAR M283 Potentiostat/Galvanostat using M270 chronoamperometry software.

A Au/4(ZrAV2P) electrode prepared in Example 44 was used as a workingelectrode, with Pt serving as a counter electrode (2 electrode circuit),and, in a separate measurement, with SCE as a reference electrode and Ptas a counter electrode (3 electrode circuit). The Au/4(ZrAV2P) electrodewas illuminated with 200 W Hg/Xe lamp with a filter cutting off UV lightbelow 360 nm. Illuminated area of the electrode was ˜0.5 cm2.

The results of these tests are shown in the graph of FIG. 5

EXAMPLE 46

Photochemistry of Film of Example 44

Photoelectrochemical measurements were performed in a quartz cellcontaining 0.1 M NaClO4 (supporting electrolyte) and 10-2 M Eu(NO3)3(electron acceptor). Dark currents and photocurrents were measured withPAR M283 Potentiostat/Galvanostat using M270 chronoamperometry software.

A Au/4(ZrAV2P) electrode prepared in Example 44 was used as a workingelectrode, with Pt serving as a counter electrode (2 electrode circuit),and, in a separate measurement, with SCE as a reference electrode and Ptas a counter electrode (3 electrode circuit). The Au/4(ZrAV2P) electrodewas illuminated with 200 W Hg/Xe lamp. Illuminated area of the electrodewas ˜0.5 cm2.

The results of these tests are shown in the graph of FIG. 6.

EXAMPLE 47

Preparation of Au/4(ZrDABP)/4(ZrAV2P) photoelectrode:

Gold foil (0.1 mm thick) was cut into pieces 2×50 mm2 and cleaned in aconcentrated HNO3 for 10 min, then thoroughly rinsed with distilledwater and 100% ethanol. Self-assembled films of(3-mercaptopropyl)trimethoxysilane (3-MPT) were formed by immersion ofAu foil into solution of 20 mM 3-MPT in 100% ethanol for 2 hours at roomtemperature. (See e.g., W. R. Thompson, J. E. Pemberton, Thin Sol-GelSilica Films on (3-Mercaptopropyl) trimethoxysilane modified Ag and Auelectrodes, Chem. Mater. 7, 130-136 (1995)). Then Au was rinsed with100% ethanol and allowed to air-dry. Hydrolysis of the 3-MPT modifiedsurface was then achieved by immersion into an aqueous 0.1 M solution ofHCl for 12 hours at room temperature. The surface was zirconated bydipping the foil into 60 mM ZrOCl2 aqueous solution for 2 hours at roomtemperature.

DABP (H₂ O₃ P--(CH₂)--C₆ H₄ --N═N--C₆ H₄ --(CH₂)--PO₃ H₂) wassynthesized using standard literature procedures. ZrDABP/ZrAV2P film wasgrown by alternate treatment in 10 mM DABP solution at 80° C. for 4hours and in 60 mM ZrOCl2 aqueous solution at room temperature for 2hours (4 cycles of deposition), then by alternate treatment in 10 mMAV2P solution at 80° C. for 4 hours and in 60 mM ZrOCl2 aqueous solutionat room temperature for 2 hours (next 4 cycles of deposition).

EXAMPLE 48

Photochemistry of Film of Example 47

Photoelectrochemical measurements were performed in a quartz cellcontaining 0.1 M NaClO4 (supporting electrolyte) and 10-2 M Eu(NO3)3(electron acceptor). Dark currents and photocurrents were measured withPAR M283 Potentiostat/Galvanostat using M270 chronoamperometry software.

A Au/4(ZrDABP)/4(ZrAV2P) electrode prepared in Example 47 was used as aworking electrode, with Pt serving as a counter electrode (2 electrodecircuit), and, in a separate measurement, with SCE as a referenceelectrode and Pt as a counter electrode (3 electrode circuit). TheAu/4(ZrDABP)/4(ZrAV2P) electrode was illuminated with 200 W Hg/Xe lampwith a filter cutting off the UV light below 420 nm. Illuminated area ofthe electrode was ˜0.5 cm2.

The results of these tests are shown in the graph of FIG. 7.

EXAMPLE 49

Photochemistry of Film of Example 47

Photoelectrochemical measurements were performed in a quartz cellcontaining 0.1 M NaClO4 (supporting electrolyte) and 10-2 M Eu(NO3)3(electron acceptor). Dark currents and photocurrents were measured withPAR M283 Potentiostat/Galvanostat using M270 chronoamperometry software.

A Au/4(ZrDABP)/4(ZrAV2P) electrode prepared in Example 47 was used as aworking electrode, with Pt serving as a counter electrode (2 electrodecircuit), and, in a separate measurement, with SCE as a referenceelectrode and Pt as a counter electrode (3 electrode circuit). TheAu/4(ZrDABP)/4(ZrAV2P) electrode was illuminated with 200 W Hg/Xe lampwith a filter cutting off the UV light below 360 nm. Illuminated area ofthe electrode was ˜0.5 cm2.

The results of these tests are shown in the graph of FIG. 8.

EXAMPLE 50

Photochemistry of Film of Example 47

Photoelectrochemical measurements were performed in a quartz cellcontaining 0.1 M NaClO4 (supporting electrolyte) and 10-2 M Eu(NO3)3(electron acceptor). Dark currents and photocurrents were measured withPAR M283 Potentiostat/Galvanostat using M270 chronoamperometry software.

A Au/4(ZrDABP)/4(ZrAV2P) electrode prepared in Example 47 was used as aworking electrode, with Pt serving as a counter electrode (2 electrodecircuit), and, in a separate measurement, with SCE as a referenceelectrode and Pt as a counter electrode (3 electrode circuit). TheAu/4(ZrDABP)/4(ZrAV2P) electrode was illuminated with 200 W Hg/Xe lamp.Illuminated area of the electrode was ˜0.5 cm2.

The results of these tests are shown in the graph of FIG. 9.

EXAMPLE 51

Preparation of Au/4(ZrPAPD)/4(ZrAV2P) Photoelectrode:

Gold foil (0.1 mm thick) was cut into pieces 2×50 mm2 and cleaned in aconcentrated HNO3 for 10 min, then thoroughly rinsed with distilledwater and 100% ethanol. Self-assembled films of(3-mercaptopropyl)trimethoxysilane (3-MPT) were formed by immersion ofAu foil into solution of 20 mM 3-MPT in 100% ethanol for 2 hours at roomtemperature. (See e.g., W. R. Thompson, J. E. Pemberton, Thin Sol-GelSilica Films on (3-Mercaptopropyl) trimethoxysilane modified Ag and Auelectrodes, Chem. Mater. 7, 130-136 (1995)). Then Au was rinsed with100% ethanol and allowed to air-dry. Hydrolysis of the 3-MPT modifiedsurface was then achieved by immersion into an aqueous 0.1 M solution ofHCl for 12 hours at room temperature. The surface was zirconated bydipping the foil into 60 mM ZrOCl2 aqueous solution for 2 hours at roomtemperature.

ZrPAPD/ZrAV2P film was grown by alternate treatment in 10 mM PAPDsolution at 80° C. for 4 hours and in 60 mM ZrOCl2 aqueous solution atroom temperature for 2 hours (4 cycles of deposition), then by alternatetreatment in 10 MM AV2P solution at 80° C. for 4 hours and in 60 mMZrOCl2 aqueous solution at room temperature for 2 hours (next 4 cyclesof deposition).

EXAMPLE 52

Photochemistry of Film of Example 51

Photoelectrochemical measurements were performed in a quartz cellcontaining 0.1 M NaClO4 (supporting electrolyte) and 10-2 M Eu(NO3)3(electron acceptor). Dark currents and photocurrents were measured withPAR M283 Potentiostat/Galvanostat using M270 chronoamperometry software.

A Au/4(ZrPAPD)/4(ZrAV2P) electrode prepared in Example 51 was used as aworking electrode, either with Pt serving as a counter electrode (2electrode circuit), or with SCE as a reference electrode and Pt as acounter electrode (3 electrode circuit). The Au/4(ZrPAPD)/4(ZrAV2P)electrode was illuminated with 200 W Hg/Xe lamp. Illuminated area of theelectrode was ˜0.5 cm2.

The results of these tests are shown in the graph of FIG. 10.

EXAMPLE 53

Preparation of Au/4(PAPD)/4(PV) Electrode:

A gold substrate was treated with thiophosphonic acid (HS(CH₂)₄ PO₃ H₂).The surface was then zirconated. (See e.g., W. R. Thompson, J. E.Pemberton, Thin Sol-Gel Silica Films on (3-Mercaptopropyl)trimethoxysilane modified Ag and Au electrodes, Chem. Mater. 7, 130-136(1995)).

ZrPAPD/ZrPV film was grown by alternate treatment in PAPD solution andin ZrOCl2 aqueous solution at room temperature (4 cycles ofdeposition)., then by alternate treatment in PV solution and in ZrOCl2aqueous solution at room temperature(next 4 cycles of deposition).

EXAMPLE 54

Photochemistry of Example 53

Current Density Versus Time for the Au/4(PAPD)/4(PV) Electrode.

The potential was set to 0.0V versus SCE. Currents were obtained using atwo electrode cell in a 0.1 M NaClO₄ aqueous solution. The dark currentis measured when no light is irradiating the sample. The current versustime was monitored with zero applied potential in the dark until thesystem stabilized, usually 3-4 min. The Au°PAPD/PV electrode was thenexposed to light for approximately the same length of time and was thencycled back and forth between dark and light exposure.

Photocurrents were registered using a PAR potientiostat/GalvanostatModel 683 in a 0.1 M NaClO₄ aqueous solution two electrode cell. Theworking electrode was the Au°PAPD/PV film-covered gold of Example 53 andthe reference electrode (SCE) served also as the counter electrode.Measurements were also repeated using a three electrode cell and theresults were identical, although the signal-to-noise ratio decreased.

Results are show in the graph of FIG. 11

EXAMPLE 55

Preparation of Au/4(PV)/4(PAPD) Electrode:

A gold substrate was treated with thiophosphonic acid (HS(CH₂)₄ PO₃ H₂).The surface was then zirconated. (See e.g., W. R. Thompson, J. E.Pemberton, Thin Sol-Gel Silica Films on (3-Mercaptopropyl)trimethoxysilane modified Ag and Au electrodes, Chem. Mater. 7, 130-136(1995)).

ZrPV/ZrPAPD was grown by alternate treatment in PV solution and inZrOCl2 aqueous solution at room temperature (4 cycles of deposition),then by alternate treatment in PAPD solution and in ZrOCl2 aqueoussolution at room temperature(next 4 cycles of deposition).

EXAMPLE 56

Photochemistry of Example 55

Current Density Versus Time for the Au/4(PV)/4(PAPD) Electrode.

The potential was set to 0.0 V versus SCE. Currents were obtained usinga two electrode cell in a 0.1 M EDTA aqueous solution under anaerobicconditions. The dark current is measured when no light is irradiatingthe sample. Photocurrents were obtained using an unfiltered 200 W Hg/Xelamp. Positive current indicates the electrons flow to the goldelectrode.

Results are show in the graph of FIG. 12.

EXAMPLE 57

Preparation of Au/4(PAPD)/4(VBP) Electrode:

A gold substrate was treated with thiophosphonic acid (HS(CH₂)₄ PO₃ H₂).The surface was then zirconated. (See e.g., W. R. Thompson, J. E.Pemberton, Thin Sol-Gel Silica Films on (3-Mercaptopropyl)trimethoxysilane modified Ag and Au electrodes, Chem. Mater. 7, 130-136(1995)).

ZrPAPD/ZrVBP was grown by alternate treatment in PAPD solution and inZrOCl2 aqueous solution at room temperature (4 cycles of deposition),then by alternate treatment in VBP solution and in ZrOCl2 aqueoussolution at room temperature(next 4 cycles of deposition).

EXAMPLE 58

Photochemistry of Example 57

Current Density Versus Time for the Au/4(PAPD)/4(VBP) Electrode.

The potential was set to 0.0V versus SCE. Currents were obtained using atwo electrode cell in a 0.1 M NaClO₄ aqueous solution. The dark currentis measured when no light is irradiating the sample. Photocurrents wereobtained using a 200 W Hg/Xe lamp with a UV filter (>330 nm). Negativecurrent indicates the electrons, flow from the gold electrode.

Results are show in the graph of FIG. 13.

What is claimed is:
 1. A photovoltaic device comprising a supportingsubstrate having on its surface a heterolamellar film having one or morecharge donating layers and one or more charge accepting layers, eachlayer comprising(i) a plurality of a complex of the formula:

    [(Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3)Me.sup.Y ].sub.k.k*p(X.sup.q-)

whereineach of Y¹ and Y², independently of the other, is phosphorus orarsenic; Z is a divalent group which reversibly forms a stable reducedform and stable oxidized form;X is an anion; Me^(Y) is Me¹ _(n) W_(m),whereMe¹ is a divalent, trivalent, or tetravalent metal of Group III,IVA, or IVB having an atomic number of at least 21 or a lanthanide; W isan anion; n is 1, 2, or 3; m is 0, 1, 2, 3, or 4; k has a value of from1 to about 250; p has a value of 0, 1, 2, or 3; and q is the charge onX,wherein each of Y¹, Y², Z, and Me¹ may be different for each layer;ii) one or more charge generator layers between said one or more chargedonating layers and one or more charge accepting layers;wherein saidfilm is bound to said substrate through a linking means.
 2. Thephotovoltaic device of claim 1, wherein the film further comprisescolloidal particles of at least one Group VIII metal at zero valenceentrapped within said complexes by the Me¹ atoms.
 3. The photovoltaicdevice of claim 1, wherein said charge generating layer is comprised ofa stilbazole or an asymmetric diazole.
 4. A method for producingelectrical energy comprising exposing a photovoltaic device to light,wherein said photovoltaic device comprises the device of claim
 1. 5. Aphotovoltaic device for producing a photocurrent comprising a supportingsubstrate having on its surface a heterolamellar film comprising:atleast one donor layer, at least one acceptor layer and at least onecharge generator layer; said donor layer having electron donatingproperties relative to said acceptor layer; and, said acceptor layerhaving electron accepting properties relative to said donor layer; saidcharge generator layer comprised of a plurality of charge generatorshaving an excited state characterized by a large dipole moment; whereinsaid charge generator layer is located between said donor layer and saidacceptor layer.
 6. The photovoltaic device of claim 5 whereineach ofsaid donor and acceptor layers, independently of the other, comprisesone or more sub-layers, each sub-layer having a pillar-layer comprisedof a plurality of organic pillars illustrated by the formula:

    --(Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3)--.p(X.sup.-q)

each of Y¹ and Y², independently of the other, is phosphorous orarsenic;Z is capable of alternating between a stable reduced form and astable oxidized form, wherein Z may be different for each sub-layer ofpillars; X is an anion; p has a value of 0, 1, 2 or 3; and, q is thecharge on X; and a metal layer comprised of:a) atoms of a trivalent ortetravalent metal of Group III, IVA, IVB having an atomic number of atleast 21 or atoms of a lanthanide, forming a cohesive layer; and, b)anions bound to the metal atoms such that the metal ions have alleffective valence of from ⁺ 1 to ⁺ 6; and said charge generating layercomprises one or more sub-layers, each sub-layer having a pillar-layercomprised of a plurality of organic pillars illustrated by the formula:

    --(Y.sup.1 O.sub.3 --Z--Y.sup.2 O.sub.3)--.p(X.sup.-q)

each of Y¹ and Y², independently of the other, is phosphorous orarsenic;Z has an uncharged form and a zwitterionic form; X is an anion;p has a value of 0, 1, 2 or 3; and, q is the charge on X; and a metallayer comprised of:a) atoms of a trivalent or tetravalent metal of GroupIII, IVA, IVB having an atomic number of at least 21 or atoms of alanthanide, forming, a cohesive layer; and, b) anions bound to the metalatoms such that the metal ions have an effective valence of from ⁺ 1 to⁺ 6;wherein said heterolamellar film is attached to the substrate by alinking means.
 7. The photovoltaic device of claim 5 comprising two ormore donor layers and two or more acceptor layers; wherein individualdonor layers are ordered alternately with individual acceptor layers. 8.The photovoltaic device of claim 7 wherein said two or more donorsub-layers have the same formula and the same electron donatingproperties and, said two or more acceptor sub-layers have the sameformula and the same electron accepting properties.
 9. The photovoltaicdevice of claim 7 wherein said each of said two or more donor sub-layershave a different formula and different electron donating properties andeach of said two or more acceptor sub-layers have a different formulaand different electron accepting properties.
 10. The photovoltaic deviceof claim 5 wherein said donor layer comprises two or more sub-layers andsaid acceptor layer comprises two or more sub-layers.
 11. Thephotovoltaic device of claim 5 wherein Z for said charge generator layeris selected from the group consisting of stilbazolium compounds andasymmetric diazo compounds.